Team:Worldshaper-Shanghai/Description
Project Discription
INSPIRATION AND DESCRIPTION
Members of Worldshaper-Shanghai are all high school students, gathering because of our enthusiasm in medical knowledge. Considering most of the team members are interested in cancer, we decided to design a product which can make the diagnosis of cancer much easier.
Through public surveys and offline publicity activities, we found that the public is very resistant to the topic of prostate and lacks awareness of prevention and treatment of prostate cancer. From professor interviews, we recognized that the cure rate of the early stage of cancer is relatively higher. However, when most patients are diagnosed with prostate cancer, the disease has advanced to the middle and late stages. Therefore, it is urgent and meaningful to develop early diagnosis techniques. At the same time, protecting patient privacy and ease of operation are also issues that must be considered.
In conclusion, the mentioned above inspired us to design a non-invasive and sensitive device to diagnose early prostate cancer.
BACKGROUND
1.Introduction of prostate cancer
Prostate Cancer is the abnormal propagation of cells in the prostate tissues[1], a gland located below the bladder, above the penis. This disease is the third leading cause of all men's cancer deaths. New cases increase with an increment of 0.66 million each year[2].
Overall, the risk of getting the disease increases with age. While other factors are unified, the incidence of prostate cancer can increase from 4% for these with an age below 30 to 49% for these above 79. Worse aging causes a deteriorate of prostate cancer.
Genetically, due to the lack of obvious early symptoms and privacy reasons, the proportion of patients diagnosed with prostate cancer is relatively high, which increases the difficulty of treatment and affects the prognosis of patients[3].
The survival rate of regional prostate cancer in 5 years is fairly high, about 100%, and in 10 years it will decrease to 98%. But prostate cancer at advanced stages can be very dangerous to humans. But the patients with prostate cancer that has spread to other gland and tissue, the survival rate will be 30% only in 5 year-time. Prostate cancer can also bring complications such as metastasizes. It means that cancer has spread to other areas such as the bladder or bones. As the data shows, it is unlikely to be cured. Also, men who have prostate cancer have a higher chance of getting a “second cancer”, this includes small intestine cancer, soft tissue cancer, bladder cancer, thyroid cancer, thymus cancer, and Melanoma of the skin.
Therefore, improving the screening rate of early prostate cancer is of great significance for the treatment of prostate cancer.
2.Current diagnosis techniques
Our team got some information about current prostate cancer diagnosis technology after interviewing three urology or laboratory experts from Shanghai Changhai Hospital, Shanghai East Hospital, and Shanghai Gongli hospital. There are several ways to diagnose prostate cancer, including DRE (Digital rectal examination), TRUS (Transrectal ultrasound), MRI (Magnetic Resonance Imaging), and Serum PSA (Prostate-specific antigen). And the most reliable way is the prostate biopsy, which is usually used as a further confirmed way when abnormal or suspicious found in the above-mentioned screening method.
DRE (Digital Rectal Examination):
DRE is the most mature way of diagnosing prostate cancer currently, which during the process, a gloved finger is inserted into the patients’ rectum to check the prostate gland adjacent to it. DRE is easy to perform, and can usually find relatively large prostate cancer nodules. Also, there is evidence that DRE by primary care clinicians can show discrimination between benign and malignant conditions affecting the prostate[4].
However, DRE has some inevitable problems. Firstly, small lesions located on the sides of the peripatetic belt or near the transitional zone are not easy to feel and are subjective and insensitive to diagnosis. Secondly, some men felt a loss of personal dignity after undergoing the invasive procedure of screening, which makes them afraid of DRE[5].In conclusion, the specificity of DRE is high, but the sensitivity is poor[6].
TRUS (Transrectal ultrasound):
Transrectal ultrasound (TRUS) is a method of transrectal ultrasound examination, which is also the most commonly used screening method for prostate cancer. It involves the placement of an ultrasound probe inserted through the rectos to reach the prostate. The ultrasound probe can be directly placed on the prostate to show a clear image of small lesions, especially micro cancers.
MRI (Magnetic Resonance Imaging):
Magnetic Resonance Imaging (MRI) is a kind of tomography, which uses the phenomenon of magnetic resonance to obtain the electromagnetic signal from the human body and reconstruct its information. It can be used to obtain sectional images in any direction, three-dimensional volume images, and even four-dimensional images of spatial-spectral distribution. Thus this technology is of great value for qualitative diagnosis and localization of prostate lesions.
The employment of MRI can help to:
(1) reduce the proportion of men having unnecessary biopsies;
(2) improve the detection rate of prostate cancer;
(3) increase the cost efficiency of prostate cancer diagnostic and therapeutic pathway[7].
However, MRI can prove much more expensive than conventional diagnostic methods and has a lower rate of detecting smaller tumors.
Serum PSA (Prostate-specific antigen)：
PSA testing is one of the most used forms of prostate cancer screening, because of ease to perform thereby increasing the diagnosis rate of prostate cancer to some extent[8]. However, prostatic hyperplasia, acute urinary retention, prostatitis, rectum Digital examination, cystoscopy, ejaculation, and rubbing of the genitals will all cause blood serum PSA to rise significantly. Therefore, PSA screening has long been criticized for its inaccuracy. Also, the risk still exists during the process of getting blood.
OUR IMPROVEMENTS
In view of the above survey results, we have clarified the goal of our project, which is to develop a convenient, low-cost, and highly specific early screening method for prostate cancer.
Test sample selection:
Finding a suitable test sample is the first step of our project. After comparing various available samples, we set our sights on the urine sample.Urine contains a lot of substrates that can be used as biomarkers. Various types of prostate biomarkers will be released into the urine, including cell-related markers and secreted cell-free markers (such as nucleic acids, proteins, metabolites, etc.) Also, urine has low background interference than blood, which could improve the detection ability[9-10]. Considering that the urine test is the simplest, painless, and rapid test method, it can be done only by providing urine and should be checked actively to facilitate further diagnosis.
Biomarkers in urine sample:
We also chose new biomarkers for the diagnosis of prostate cancer. We read a large number of literates and found that there are several clinical urine tests for prostate cancer detection. The detection of mRNA in urine is one of the important indexes. We narrowed the range of candidate mRNA and identified them among six biomarkers: PCA3, AMACR, GOLM1, HOXC6, KLK3, and PSMA[10-21]. We searched the above genes by using the website GEPIA2[22] to determine the specificity and sensitivity of each biomarker in prostate cancer tissues (Gepia2，http://gepia2.cancer-pku.cn/#index, is a website developed by Zhang's Lab of Peking University. It can analyze the RNA SEQ expression data of 9736 tumor samples and 8587 normal samples from TCGA and GTEX projects). We got the following results (Figure 1).
Figure 1: The gene expression profile of 6 candidate genes across all tumor samples and paired normal tissues on GEPIA2 website
*Notes: The graph above shows the gene expression profile across all tumor samples and paired normal tissues. On the X-axis of the graph, the PRAD relates to Prostate adenocarcinoma (prostate cancer), and the rest of the means of other cancers. And the higher the number is, the higher the expression level does the gene has.
From the statistics and the graphs, we can easily find that AMACR, GOLM1, and HOXC6 are expressed in both normal tissues and tumor samples, which will lead to confusion between prostate cancer and other kinds of tumors. PSMA may be better than the three that we mentioned above, but it still expresses in most the other cancers, though just a little. Compared with PSMA, we can find that PCA3 and KLK3 almost do not express in other cancers or just a little that can be ignored. This means that both of them have high specificity in prostate cancer. Moreover, the expression of these two genes was significantly different between prostate cancer cells and normal cells, which shows a high sensitivity. In conclusion, considering the sensitivity and the specificity, we choose KLK3 and PCA3 as the biomarkers.
Readout way
To ensure the simplicity and ease operate of the method, the readout way is another issue that needs to be considered. After consulting the wikis of the former iGEM teams, we studied the project designs and descriptions of the 2019 Best Diagnostics Project for Undergraduates (Team ‘Thessaly’) and found that they incorporated the toehold switch into their diagnosis mechanism. In addition, a clear display of results (usage of red fluorescent proteins) is also preferred for us, which can further reduce operational barriers and provide intuitive warnings for prostate cancer patients. (Please see more details on our DESIGNpage）
OUR PROJECT
This year, our team, Worldshaper-Shanghai, plan to develop a novel non-invasive urine diagnosis kit to screen prostate cancer, which uses PCA3 and KLK3 as biomarkers and show visible readout if the user has prostate cancer with the help of toehold switch. We plan to extend the urine diagnosis kit to community hospitals or physical examination centers that are closer to patients. This avoids the inconvenience of testing at large hospitals and having to wait a long time for the results. Also, people can choose prostate cancer screening on their checklists in physical examination centers, increasing the probability for men to find out that they have the tumor in the early stages.
REFERENCE
[1] Litwin, Mark S., and Hung-Jui Tan. "The diagnosis and treatment of prostate cancer: a review." Jama 317.24 (2017): 2532-2542.
[2] Li Ruicen, et al. "Research progress of prostate cancer-related risk factors." practical journal of clinical medicine 16.01(2019):205-207.
[3] Bell, Katy JL, et al. "Prevalence of incidental prostate cancer: a systematic review of autopsy studies." International journal of cancer 137.7 (2015): 1749-1757.
[4] Naji, Leen, et al. "Digital Rectal Examination for Prostate Cancer Screening in Primary Care: A Systematic Review and Meta-Analysis." Annals of Family Medicine 16.2(2018):149.
[5] James, Laura J., et al. "Men's perspectives of prostate cancer screening: A systematic review of qualitative studies." Plus One12.11(2017):e0188258.
[6] Liu Junting, Zhang Wen, and Liang Li. "Analysis of the diagnostic value of serum t-PSA, f-PSA/t-PSA, DRE, and TRUS in prostate cancer." Chinese Journal of laboratory diagnosis 04(2012):650-653
[7] Zhu K, Qin Z, Xue J, et al. Comparison of prostate cancer detection rates between magnetic resonance imaging-targeted biopsy and transrectal ultrasound-guided biopsy according to Prostate Imaging Reporting and Data System in patients with PSA ≥4 ng/mL: a systematic review and meta-analysis. Transl Androl Urol. 2019;8(6):741-753. DOI:10.21037/tau.2019.12.03
[8] Schoots IG, Roobol MJ, Nieboer D, Bangma CH, Steyerberg EW, Hunink MG. Magnetic resonance imaging-targeted biopsy may enhance the diagnostic accuracy of significant prostate cancer detection compared to standard transrectal ultrasound-guided biopsy: a systematic review and meta-analysis. Eur Urol. 2015;68(3):438-450. DOI:10.1016/j.eururo.2014.11.037
[9] Eskra J N, Rabizadeh D, Pavlovich CP, et al. Approaches to urinary detection of prostate cancer[J]. Prostate Cancer and Prostatic Diseases, 2019.]
[10] Julian BA, Suzuki H, Suzuki Y, Tomino Y, Spasovski G, Novak J. Sources of urinary proteins and their analysis by urinary proteomics for the detection of biomarkers of disease. Proteomics Clin Appl. 2009;3:1029–43.
[11] Bussemakers MJ, van Bokhoven A, Verhaegh GW, Smit FP, Karthaus HF, Schalken JA, et al. DD3: a new prostate-specific gene, highly overexpressed in prostate cancer. Cancer Res. 1999;59:5975–9.
[12] Deras IL, Aubin SM, Blase A, Day JR, Koo S, Partin AW, et al. PCA3: a molecular urine assay for predicting prostate biopsy outcome. J Urol. 2008;179:1587–92.
[13] Wei JT, Feng Z, Partin AW, Brown E, Thompson I, Sokoll L, et al. Can urinary PCA3 supplement PSA in the early detection of prostate cancer?. J Clin Oncol. 2014;32:4066–72.
[14] McKiernan J, Donovan MJ, O’Neill V, Bentinck S, Noerholm M, Belzer S, et al. A novel urine exosome gene expression assay to predict high-grade prostate cancer at initial biopsy. JAMA Oncol. 2016;2:882–9.
[15] Donovan MJ, Noerholm M, Bentink S, Belzer S, Skog J, O’Neill V, et al. A molecular signature of PCA3 and ERG exosomal RNA from non-DRE urine is predictive of initial prostate biopsy result. Prostate Cancer Prostatic Dis. 2015;18: 370–5.
[16] Leyten GH, Hessels D, Smit FP, Jannink SA, de Jong H, Mel- chers WJ, et al. Identification of a candidate gene panel for the early diagnosis of prostate cancer. Clin Cancer Res. 2015;21:3061–70.
[17] Van Neste L, Hendriks RJ, Dijkstra S, Trooskens G, Cornel EB, Jannink SA, et al. Detection of high-grade prostate cancer using a urinary molecular biomarker–based risk score. Eur Urol. 2016;70:740–8.
[18] Salami SS, Schmidt F, Laxman B, Regan MM, Rickman DS, Scherr D, et al. Combining urinary detection of TMPRSS2: ERG and PCA3 with serum PSA to predict a diagnosis of prostate cancer. Urol Oncol. 2013;31:566–71.
[19] Sanda MG, Feng Z, Howard DH, et al. Association between combined TMPRSS2: ERG and PCA3 RNA urinary testing and detection of aggressive prostate cancer. JAMA Oncol. 2017;3:1085–93.97.
[20] McDunn JE, Li Z, Adam K-P, Neri BP, Wolfert RL, Milburn MV, et al. Metabolomic signatures of aggressive prostate cancer. Prostate. 2013;73:1547–60.98.
[21] McDunn JE, Stirdivant SM, Ford LA, Wolfert RL. Metabo- comics and its application to the development of clinical laboratory tests for prostate cancer. EJIFCC. 2015;26:92–104.
[22] Tang, Z. et al. (2017) GEPIA: a web server for cancer and normal gene expression profiling and interactive analyses. Nucleic Acids Res, 10.1093/nar/gkx247.
The survival rate of regional prostate cancer in 5 years is fairly high, about 100%, and in 10 years it will decrease to 98%. But prostate cancer at advanced stages can be very dangerous to humans. But the patients with prostate cancer that has spread to other gland and tissue, the survival rate will be 30% only in 5 year-time. Prostate cancer can also bring complications such as metastasizes. It means that cancer has spread to other areas such as the bladder or bones. As the data shows, it is unlikely to be cured. Also, men who have prostate cancer have a higher chance of getting a “second cancer”, this includes small intestine cancer, soft tissue cancer, bladder cancer, thyroid cancer, thymus cancer, and Melanoma of the skin.
Therefore, improving the screening rate of early prostate cancer is of great significance for the treatment of prostate cancer.
2.Current diagnosis techniques
Our team got some information about current prostate cancer diagnosis technology after interviewing three urology or laboratory experts from Shanghai Changhai Hospital, Shanghai East Hospital, and Shanghai Gongli hospital. There are several ways to diagnose prostate cancer, including DRE (Digital rectal examination), TRUS (Transrectal ultrasound), MRI (Magnetic Resonance Imaging), and Serum PSA (Prostate-specific antigen). And the most reliable way is the prostate biopsy, which is usually used as a further confirmed way when abnormal or suspicious found in the above-mentioned screening method.
DRE (Digital Rectal Examination):
DRE is the most mature way of diagnosing prostate cancer currently, which during the process, a gloved finger is inserted into the patients’ rectum to check the prostate gland adjacent to it. DRE is easy to perform, and can usually find relatively large prostate cancer nodules. Also, there is evidence that DRE by primary care clinicians can show discrimination between benign and malignant conditions affecting the prostate[4].
However, DRE has some inevitable problems. Firstly, small lesions located on the sides of the peripatetic belt or near the transitional zone are not easy to feel and are subjective and insensitive to diagnosis. Secondly, some men felt a loss of personal dignity after undergoing the invasive procedure of screening, which makes them afraid of DRE[5].In conclusion, the specificity of DRE is high, but the sensitivity is poor[6].
TRUS (Transrectal ultrasound):
Transrectal ultrasound (TRUS) is a method of transrectal ultrasound examination, which is also the most commonly used screening method for prostate cancer. It involves the placement of an ultrasound probe inserted through the rectos to reach the prostate. The ultrasound probe can be directly placed on the prostate to show a clear image of small lesions, especially micro cancers.
MRI (Magnetic Resonance Imaging):
Magnetic Resonance Imaging (MRI) is a kind of tomography, which uses the phenomenon of magnetic resonance to obtain the electromagnetic signal from the human body and reconstruct its information. It can be used to obtain sectional images in any direction, three-dimensional volume images, and even four-dimensional images of spatial-spectral distribution. Thus this technology is of great value for qualitative diagnosis and localization of prostate lesions.
The employment of MRI can help to:
(1) reduce the proportion of men having unnecessary biopsies;
(2) improve the detection rate of prostate cancer;
(3) increase the cost efficiency of prostate cancer diagnostic and therapeutic pathway[7].
However, MRI can prove much more expensive than conventional diagnostic methods and has a lower rate of detecting smaller tumors.
Serum PSA (Prostate-specific antigen)：
PSA testing is one of the most used forms of prostate cancer screening, because of ease to perform thereby increasing the diagnosis rate of prostate cancer to some extent[8]. However, prostatic hyperplasia, acute urinary retention, prostatitis, rectum Digital examination, cystoscopy, ejaculation, and rubbing of the genitals will all cause blood serum PSA to rise significantly. Therefore, PSA screening has long been criticized for its inaccuracy. Also, the risk still exists during the process of getting blood.
OUR IMPROVEMENTS
In view of the above survey results, we have clarified the goal of our project, which is to develop a convenient, low-cost, and highly specific early screening method for prostate cancer.
Test sample selection:
Finding a suitable test sample is the first step of our project. After comparing various available samples, we set our sights on the urine sample.Urine contains a lot of substrates that can be used as biomarkers. Various types of prostate biomarkers will be released into the urine, including cell-related markers and secreted cell-free markers (such as nucleic acids, proteins, metabolites, etc.) Also, urine has low background interference than blood, which could improve the detection ability[9-10]. Considering that the urine test is the simplest, painless, and rapid test method, it can be done only by providing urine and should be checked actively to facilitate further diagnosis.
Biomarkers in urine sample:
We also chose new biomarkers for the diagnosis of prostate cancer. We read a large number of literates and found that there are several clinical urine tests for prostate cancer detection. The detection of mRNA in urine is one of the important indexes. We narrowed the range of candidate mRNA and identified them among six biomarkers: PCA3, AMACR, GOLM1, HOXC6, KLK3, and PSMA[10-21]. We searched the above genes by using the website GEPIA2[22] to determine the specificity and sensitivity of each biomarker in prostate cancer tissues (Gepia2，http://gepia2.cancer-pku.cn/#index, is a website developed by Zhang's Lab of Peking University. It can analyze the RNA SEQ expression data of 9736 tumor samples and 8587 normal samples from TCGA and GTEX projects). We got the following results (Figure 1).
Figure 1: The gene expression profile of 6 candidate genes across all tumor samples and paired normal tissues on GEPIA2 website
*Notes: The graph above shows the gene expression profile across all tumor samples and paired normal tissues. On the X-axis of the graph, the PRAD relates to Prostate adenocarcinoma (prostate cancer), and the rest of the means of other cancers. And the higher the number is, the higher the expression level does the gene has.
From the statistics and the graphs, we can easily find that AMACR, GOLM1, and HOXC6 are expressed in both normal tissues and tumor samples, which will lead to confusion between prostate cancer and other kinds of tumors. PSMA may be better than the three that we mentioned above, but it still expresses in most the other cancers, though just a little. Compared with PSMA, we can find that PCA3 and KLK3 almost do not express in other cancers or just a little that can be ignored. This means that both of them have high specificity in prostate cancer. Moreover, the expression of these two genes was significantly different between prostate cancer cells and normal cells, which shows a high sensitivity. In conclusion, considering the sensitivity and the specificity, we choose KLK3 and PCA3 as the biomarkers.
Readout way
To ensure the simplicity and ease operate of the method, the readout way is another issue that needs to be considered. After consulting the wikis of the former iGEM teams, we studied the project designs and descriptions of the 2019 Best Diagnostics Project for Undergraduates (Team ‘Thessaly’) and found that they incorporated the toehold switch into their diagnosis mechanism. In addition, a clear display of results (usage of red fluorescent proteins) is also preferred for us, which can further reduce operational barriers and provide intuitive warnings for prostate cancer patients. (Please see more details on our DESIGNpage）
OUR PROJECT
This year, our team, Worldshaper-Shanghai, plan to develop a novel non-invasive urine diagnosis kit to screen prostate cancer, which uses PCA3 and KLK3 as biomarkers and show visible readout if the user has prostate cancer with the help of toehold switch. We plan to extend the urine diagnosis kit to community hospitals or physical examination centers that are closer to patients. This avoids the inconvenience of testing at large hospitals and having to wait a long time for the results. Also, people can choose prostate cancer screening on their checklists in physical examination centers, increasing the probability for men to find out that they have the tumor in the early stages.
REFERENCE
[1] Litwin, Mark S., and Hung-Jui Tan. "The diagnosis and treatment of prostate cancer: a review." Jama 317.24 (2017): 2532-2542.
[2] Li Ruicen, et al. "Research progress of prostate cancer-related risk factors." practical journal of clinical medicine 16.01(2019):205-207.
[3] Bell, Katy JL, et al. "Prevalence of incidental prostate cancer: a systematic review of autopsy studies." International journal of cancer 137.7 (2015): 1749-1757.
[4] Naji, Leen, et al. "Digital Rectal Examination for Prostate Cancer Screening in Primary Care: A Systematic Review and Meta-Analysis." Annals of Family Medicine 16.2(2018):149.
[5] James, Laura J., et al. "Men's perspectives of prostate cancer screening: A systematic review of qualitative studies." Plus One12.11(2017):e0188258.
[6] Liu Junting, Zhang Wen, and Liang Li. "Analysis of the diagnostic value of serum t-PSA, f-PSA/t-PSA, DRE, and TRUS in prostate cancer." Chinese Journal of laboratory diagnosis 04(2012):650-653
[7] Zhu K, Qin Z, Xue J, et al. Comparison of prostate cancer detection rates between magnetic resonance imaging-targeted biopsy and transrectal ultrasound-guided biopsy according to Prostate Imaging Reporting and Data System in patients with PSA ≥4 ng/mL: a systematic review and meta-analysis. Transl Androl Urol. 2019;8(6):741-753. DOI:10.21037/tau.2019.12.03
[8] Schoots IG, Roobol MJ, Nieboer D, Bangma CH, Steyerberg EW, Hunink MG. Magnetic resonance imaging-targeted biopsy may enhance the diagnostic accuracy of significant prostate cancer detection compared to standard transrectal ultrasound-guided biopsy: a systematic review and meta-analysis. Eur Urol. 2015;68(3):438-450. DOI:10.1016/j.eururo.2014.11.037
[9] Eskra J N, Rabizadeh D, Pavlovich CP, et al. Approaches to urinary detection of prostate cancer[J]. Prostate Cancer and Prostatic Diseases, 2019.]
[10] Julian BA, Suzuki H, Suzuki Y, Tomino Y, Spasovski G, Novak J. Sources of urinary proteins and their analysis by urinary proteomics for the detection of biomarkers of disease. Proteomics Clin Appl. 2009;3:1029–43.
[11] Bussemakers MJ, van Bokhoven A, Verhaegh GW, Smit FP, Karthaus HF, Schalken JA, et al. DD3: a new prostate-specific gene, highly overexpressed in prostate cancer. Cancer Res. 1999;59:5975–9.
[12] Deras IL, Aubin SM, Blase A, Day JR, Koo S, Partin AW, et al. PCA3: a molecular urine assay for predicting prostate biopsy outcome. J Urol. 2008;179:1587–92.
[13] Wei JT, Feng Z, Partin AW, Brown E, Thompson I, Sokoll L, et al. Can urinary PCA3 supplement PSA in the early detection of prostate cancer?. J Clin Oncol. 2014;32:4066–72.
[14] McKiernan J, Donovan MJ, O’Neill V, Bentinck S, Noerholm M, Belzer S, et al. A novel urine exosome gene expression assay to predict high-grade prostate cancer at initial biopsy. JAMA Oncol. 2016;2:882–9.
[15] Donovan MJ, Noerholm M, Bentink S, Belzer S, Skog J, O’Neill V, et al. A molecular signature of PCA3 and ERG exosomal RNA from non-DRE urine is predictive of initial prostate biopsy result. Prostate Cancer Prostatic Dis. 2015;18: 370–5.
[16] Leyten GH, Hessels D, Smit FP, Jannink SA, de Jong H, Mel- chers WJ, et al. Identification of a candidate gene panel for the early diagnosis of prostate cancer. Clin Cancer Res. 2015;21:3061–70.
[17] Van Neste L, Hendriks RJ, Dijkstra S, Trooskens G, Cornel EB, Jannink SA, et al. Detection of high-grade prostate cancer using a urinary molecular biomarker–based risk score. Eur Urol. 2016;70:740–8.
[18] Salami SS, Schmidt F, Laxman B, Regan MM, Rickman DS, Scherr D, et al. Combining urinary detection of TMPRSS2: ERG and PCA3 with serum PSA to predict a diagnosis of prostate cancer. Urol Oncol. 2013;31:566–71.
[19] Sanda MG, Feng Z, Howard DH, et al. Association between combined TMPRSS2: ERG and PCA3 RNA urinary testing and detection of aggressive prostate cancer. JAMA Oncol. 2017;3:1085–93.97.
[20] McDunn JE, Li Z, Adam K-P, Neri BP, Wolfert RL, Milburn MV, et al. Metabolomic signatures of aggressive prostate cancer. Prostate. 2013;73:1547–60.98.
[21] McDunn JE, Stirdivant SM, Ford LA, Wolfert RL. Metabo- comics and its application to the development of clinical laboratory tests for prostate cancer. EJIFCC. 2015;26:92–104.
[22] Tang, Z. et al. (2017) GEPIA: a web server for cancer and normal gene expression profiling and interactive analyses. Nucleic Acids Res, 10.1093/nar/gkx247.
The employment of MRI can help to:
(1) reduce the proportion of men having unnecessary biopsies;
(2) improve the detection rate of prostate cancer;
(3) increase the cost efficiency of prostate cancer diagnostic and therapeutic pathway[7].
However, MRI can prove much more expensive than conventional diagnostic methods and has a lower rate of detecting smaller tumors.
Finding a suitable test sample is the first step of our project. After comparing various available samples, we set our sights on the urine sample.Urine contains a lot of substrates that can be used as biomarkers. Various types of prostate biomarkers will be released into the urine, including cell-related markers and secreted cell-free markers (such as nucleic acids, proteins, metabolites, etc.) Also, urine has low background interference than blood, which could improve the detection ability[9-10]. Considering that the urine test is the simplest, painless, and rapid test method, it can be done only by providing urine and should be checked actively to facilitate further diagnosis.
We also chose new biomarkers for the diagnosis of prostate cancer. We read a large number of literates and found that there are several clinical urine tests for prostate cancer detection. The detection of mRNA in urine is one of the important indexes. We narrowed the range of candidate mRNA and identified them among six biomarkers: PCA3, AMACR, GOLM1, HOXC6, KLK3, and PSMA[10-21]. We searched the above genes by using the website GEPIA2[22] to determine the specificity and sensitivity of each biomarker in prostate cancer tissues (Gepia2，http://gepia2.cancer-pku.cn/#index, is a website developed by Zhang's Lab of Peking University. It can analyze the RNA SEQ expression data of 9736 tumor samples and 8587 normal samples from TCGA and GTEX projects). We got the following results (Figure 1).
To ensure the simplicity and ease operate of the method, the readout way is another issue that needs to be considered. After consulting the wikis of the former iGEM teams, we studied the project designs and descriptions of the 2019 Best Diagnostics Project for Undergraduates (Team ‘Thessaly’) and found that they incorporated the toehold switch into their diagnosis mechanism. In addition, a clear display of results (usage of red fluorescent proteins) is also preferred for us, which can further reduce operational barriers and provide intuitive warnings for prostate cancer patients. (Please see more details on our DESIGNpage）
[2] Li Ruicen, et al. "Research progress of prostate cancer-related risk factors." practical journal of clinical medicine 16.01(2019):205-207.
[3] Bell, Katy JL, et al. "Prevalence of incidental prostate cancer: a systematic review of autopsy studies." International journal of cancer 137.7 (2015): 1749-1757.
[4] Naji, Leen, et al. "Digital Rectal Examination for Prostate Cancer Screening in Primary Care: A Systematic Review and Meta-Analysis." Annals of Family Medicine 16.2(2018):149.
[5] James, Laura J., et al. "Men's perspectives of prostate cancer screening: A systematic review of qualitative studies." Plus One12.11(2017):e0188258.
[6] Liu Junting, Zhang Wen, and Liang Li. "Analysis of the diagnostic value of serum t-PSA, f-PSA/t-PSA, DRE, and TRUS in prostate cancer." Chinese Journal of laboratory diagnosis 04(2012):650-653
[7] Zhu K, Qin Z, Xue J, et al. Comparison of prostate cancer detection rates between magnetic resonance imaging-targeted biopsy and transrectal ultrasound-guided biopsy according to Prostate Imaging Reporting and Data System in patients with PSA ≥4 ng/mL: a systematic review and meta-analysis. Transl Androl Urol. 2019;8(6):741-753. DOI:10.21037/tau.2019.12.03
[8] Schoots IG, Roobol MJ, Nieboer D, Bangma CH, Steyerberg EW, Hunink MG. Magnetic resonance imaging-targeted biopsy may enhance the diagnostic accuracy of significant prostate cancer detection compared to standard transrectal ultrasound-guided biopsy: a systematic review and meta-analysis. Eur Urol. 2015;68(3):438-450. DOI:10.1016/j.eururo.2014.11.037
[9] Eskra J N, Rabizadeh D, Pavlovich CP, et al. Approaches to urinary detection of prostate cancer[J]. Prostate Cancer and Prostatic Diseases, 2019.]
[10] Julian BA, Suzuki H, Suzuki Y, Tomino Y, Spasovski G, Novak J. Sources of urinary proteins and their analysis by urinary proteomics for the detection of biomarkers of disease. Proteomics Clin Appl. 2009;3:1029–43.
[11] Bussemakers MJ, van Bokhoven A, Verhaegh GW, Smit FP, Karthaus HF, Schalken JA, et al. DD3: a new prostate-specific gene, highly overexpressed in prostate cancer. Cancer Res. 1999;59:5975–9.
[12] Deras IL, Aubin SM, Blase A, Day JR, Koo S, Partin AW, et al. PCA3: a molecular urine assay for predicting prostate biopsy outcome. J Urol. 2008;179:1587–92.
[13] Wei JT, Feng Z, Partin AW, Brown E, Thompson I, Sokoll L, et al. Can urinary PCA3 supplement PSA in the early detection of prostate cancer?. J Clin Oncol. 2014;32:4066–72.
[14] McKiernan J, Donovan MJ, O’Neill V, Bentinck S, Noerholm M, Belzer S, et al. A novel urine exosome gene expression assay to predict high-grade prostate cancer at initial biopsy. JAMA Oncol. 2016;2:882–9.
[15] Donovan MJ, Noerholm M, Bentink S, Belzer S, Skog J, O’Neill V, et al. A molecular signature of PCA3 and ERG exosomal RNA from non-DRE urine is predictive of initial prostate biopsy result. Prostate Cancer Prostatic Dis. 2015;18: 370–5.
[16] Leyten GH, Hessels D, Smit FP, Jannink SA, de Jong H, Mel- chers WJ, et al. Identification of a candidate gene panel for the early diagnosis of prostate cancer. Clin Cancer Res. 2015;21:3061–70.
[17] Van Neste L, Hendriks RJ, Dijkstra S, Trooskens G, Cornel EB, Jannink SA, et al. Detection of high-grade prostate cancer using a urinary molecular biomarker–based risk score. Eur Urol. 2016;70:740–8.
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