Donghui Kan

Sequence variants at the TERT-CLPTM1L locus associate with many cancer types

The common sequence variants that have recently been associated with cancer risk are particular to a single cancer type or at most two. Following up on our genome-wide scan of basal cell carcinoma, we found that rs401681[C] on chromosome 5p15.33 satisfied our threshold for genome-wide significance (OR = 1.25, P = 3.7 × 10−12). We tested rs401681 for association with 16 additional cancer types in over 30,000 cancer cases and 45,000 controls and found association with lung cancer (OR = 1.15, P = 7.2 × 10−8) and urinary bladder, prostate and cervix cancer (ORs = 1.07−1.31, all P < 4 × 10−4). However, rs401681[C] seems to confer protection against cutaneous melanoma (OR = 0.88, P = 8.0 × 10−4). Notably, most of these cancer types have a strong environmental component to their risk. Investigation of the region led us to rs2736098[A], which showed stronger association with some cancer types. However, neither variant could fully account for the association of the other. rs2736098 corresponds to A305A in the telomerase reverse transcriptase (TERT) protein and rs401681 is in an intron of the CLPTM1L gene.

Genome-wide association and replication studies identify four variants associated with prostate cancer susceptibility

We report a prostate cancer genome-wide association follow-on study. We discovered four variants associated with susceptibility to prostate cancer in several European populations: rs10934853[A] (OR = 1.12, P = 2.9 × 10−10) on 3q21.3; two moderately correlated (r2 = 0.07) variants, rs16902094[G] (OR = 1.21, P = 6.2 × 10−15) and rs445114[T] (OR = 1.14, P = 4.7 × 10−10), on 8q24.21; and rs8102476[C] (OR = 1.12, P = 1.6 × 10−11) on 19q13.2. We also refined a previous association signal on 11q13 with the SNP rs11228565[A] (OR = 1.23, P = 6.7 × 10−12). In a multivariate analysis using 22 prostate cancer risk variants typed in the Icelandic population, we estimated that carriers in the top 1.3% of the risk distribution are at a 2.5 times greater risk of developing the disease than members of the general population.

[-2]Proenzyme prostate specific antigen is more accurate than total and free prostate specific antigen in differentiating prostate cancer from benign disease in a prospective prostate cancer screening study.

PURPOSE Due to the limited specificity of prostate specific antigen for prostate cancer screening, there is an ongoing search for adjunctive biomarkers. Retrospective studies have suggested that an isoform of proenzyme prostate specific antigen called [-2]proenzyme prostate specific antigen may enhance the specificity of prostate specific antigen based screening. We examined the usefulness of this isoform in a prospective prostate cancer screening study. MATERIALS AND METHODS From a population of 2,034 men undergoing prostate cancer screening we examined the relationship between the measurement of the [-2]isoform of proenzyme prostate specific antigen (p2PSA) and prostate cancer detection. Specifically we compared the usefulness of total prostate specific antigen, the ratio of free-to-total prostate specific antigen, the ratio of p2PSA-to-free prostate specific antigen, and a formula combining prostate specific antigen, free prostate specific antigen and p2PSA (the Beckman Coulter prostate health index or phi) to predict prostate cancer in men from the study undergoing prostate biopsy with a prostate specific antigen of 2.5 to 10 ng/ml and nonsuspicious digital rectal examination. RESULTS Despite similar total prostate specific antigen (p = 0.88), percent free prostate specific antigen (p = 0.02) and %p2PSA (p = 0.0006) distinguished between positive and negative biopsy results. On ROC analysis %p2PSA (AUC 0.76) outperformed prostate specific antigen (AUC 0.50) and percent free prostate specific antigen (AUC 0.68) for differentiating between prostate cancer and benign disease. Setting the sensitivity at 88.5%, p2PSA led to a substantial improvement in specificity as well as positive and negative predictive values. The Beckman Coulter prostate health index (AUC 0.77) had the best overall performance characteristics. CONCLUSIONS This is the first prospective study to our knowledge to demonstrate that p2PSA provides improved discrimination between prostate cancer and benign disease in screened men with a prostate specific antigen of 2.5 to 10 ng/ml and a negative digital rectal examination.

Adult UrologyOncology: Prostate/Testis/Penis/Urethra[-2]Proenzyme Prostate Specific Antigen is More Accurate Than Total and Free Prostate Specific Antigen in Differentiating Prostate Cancer From Benign Disease in a Prospective Prostate Cancer Screening Study

PURPOSE Due to the limited specificity of prostate specific antigen for prostate cancer screening, there is an ongoing search for adjunctive biomarkers. Retrospective studies have suggested that an isoform of proenzyme prostate specific antigen called [-2]proenzyme prostate specific antigen may enhance the specificity of prostate specific antigen based screening. We examined the usefulness of this isoform in a prospective prostate cancer screening study. MATERIALS AND METHODS From a population of 2,034 men undergoing prostate cancer screening we examined the relationship between the measurement of the [-2]isoform of proenzyme prostate specific antigen (p2PSA) and prostate cancer detection. Specifically we compared the usefulness of total prostate specific antigen, the ratio of free-to-total prostate specific antigen, the ratio of p2PSA-to-free prostate specific antigen, and a formula combining prostate specific antigen, free prostate specific antigen and p2PSA (the Beckman Coulter prostate health index or phi) to predict prostate cancer in men from the study undergoing prostate biopsy with a prostate specific antigen of 2.5 to 10 ng/ml and nonsuspicious digital rectal examination. RESULTS Despite similar total prostate specific antigen (p = 0.88), percent free prostate specific antigen (p = 0.02) and %p2PSA (p = 0.0006) distinguished between positive and negative biopsy results. On ROC analysis %p2PSA (AUC 0.76) outperformed prostate specific antigen (AUC 0.50) and percent free prostate specific antigen (AUC 0.68) for differentiating between prostate cancer and benign disease. Setting the sensitivity at 88.5%, p2PSA led to a substantial improvement in specificity as well as positive and negative predictive values. The Beckman Coulter prostate health index (AUC 0.77) had the best overall performance characteristics. CONCLUSIONS This is the first prospective study to our knowledge to demonstrate that p2PSA provides improved discrimination between prostate cancer and benign disease in screened men with a prostate specific antigen of 2.5 to 10 ng/ml and a negative digital rectal examination.

Treatment outcomes of radical prostatectomy in potential candidates for 3 published active surveillance protocols.

OBJECTIVES To examine the treatment outcomes of men who would have been eligible for active surveillance (AS) but underwent immediate radical retropubic prostatectomy (RRP). AS protocols are designed to spare the potential morbidity of treatment to patients with low-risk prostate cancer (PCa). METHODS From a prospective RRP database, we evaluated the tumor features and treatment outcomes for men who would have met 1 of 3 published AS criteria: (1) clinically localized disease, Gleason < or = 7, and no significant comorbidities (Patel et al, J Urol. 2004;171:1520-1524) (2) T1b-T2b N0M0 disease, Gleason < or = 7, and prostate-specific antigen < or = 15 ng/mL (Choo R et al. J Urol. 2002;167:1664-1669), or (3) T1c PCa (Mohler JL et al. World J Urol. 1997;15:364-368.). RESULTS 3959, 3536, and 2330 RRP patients, respectively, would have met these AS criteria. At surgery, 3%-4% had a Gleason score of 8-10, 16%-19% had positive surgical margins, 15%-18% had extracapsular tumor extension, 3%-5% had seminal vesicle invasion, and 0.4%-1% had lymph node metastasis. The 5-year progression-free survival rate ranged from 84%-89%. Metastasis occurred in 0.1%-1.2%, and 0.1%-0.9% died of PCa. On multivariate analysis, Gleason score > 6 was the strongest predictor of biochemical progression. CONCLUSIONS A substantial proportion of men who might have been considered potential AS candidates had aggressive tumor features at RRP and/or progression. Biopsy Gleason score > 6 was the strongest predictor of adverse outcomes, highlighting the importance of limiting AS to patients with Gleason < or = 6. Overall, the accurate identification of patients with truly indolent PCa at the time of diagnosis remains challenging.

Is statin use associated with prostate cancer aggressiveness

Study Type – Therapy (case series)
Level of Evidence 4

Prostate-specific antigen velocity (PSAV) risk count improves the specificity of screening for clinically significant prostate cancer.

Study Type – Prognosis (retrospective cohort analysis)

Can Prostate Specific Antigen Velocity Thresholds Decrease Insignificant Prostate Cancer Detection

PURPOSE A controversy of current prostate specific antigen based prostate cancer screening is the over detection of potentially insignificant prostate cancer. Because PSA kinetics were previously linked to prostate cancer specific mortality, we determined whether prostate specific antigen velocity is associated with clinically significant prostate cancer. MATERIALS AND METHODS A total of 1,073 men underwent radical prostatectomy from 1992 to 2008 with data available on prostate specific antigen velocity and tumor volume. Insignificant cancer was defined by the Ohori criteria as organ confined, tumor volume 0.5 cc or less and no primary or secondary Gleason pattern 4 or 5. We calculated the proportion of men with pathologically insignificant prostate cancer stratified by prostate specific antigen velocity. RESULTS Preoperative prostate specific antigen velocity greater than 0.4 ng/ml per year was significantly associated with high grade disease (p = 0.008), positive surgical margins (p = 0.003) and seminal vesicle invasion (p = 0.007) at radical prostatectomy. Median tumor volume was also significantly higher in men with preoperative prostate specific antigen velocity greater than 0.4 ng/ml per year (3.1 vs 2.4 cc, p = 0.0001). Overall 69 men (6%) met the Ohori criteria for insignificant cancer. Patients with preoperative prostate specific antigen velocity greater than 0.4 ng/ml per year were 50% less likely to have insignificant disease (10% vs 5%, p = 0.003). CONCLUSIONS A prostate specific antigen velocity threshold of 0.4 ng/ml per year was associated with the likelihood of insignificant prostate cancer. This suggests that prostate specific antigen velocity may be a useful adjunct in prostate cancer screening to increase specificity for identifying patients with clinically significant disease.

Correlation between serum prostate-specific antigen and cancer volume in prostate glands of different sizes.

OBJECTIVES To further evaluate the relationship of prostate-specific antigen (PSA) with prostate size and tumor volume in a contemporary surgical series. Although early studies showed a strong correlation between PSA and tumor volume, it has been suggested that PSA is no longer a valid marker for prostate cancer and only correlates with prostate size. METHODS From 2003 to 2009, 1234 men with data on prostate weight and total tumor volume underwent radical prostatectomy by a single surgeon. Prostate size was classified into tertiles: small (≤ 41.2 g), medium (41.3-54.5 g), and large (≥ 54.6 g). Pearson correlation coefficients were used to examine the relationship of PSA with prostate size and tumor volume across different prostate sizes. RESULTS Median preoperative PSA was 4.9 ng/mL (standard deviation ± 4.6), mean prostate size was 51.7 g, and mean tumor volume was 5.6 cm(3). PSA had a significant correlation with prostate size only at a prostate weight ≥ 54.6 g (P = .02). Regardless of prostate size, PSA had a more robust significant correlation with tumor volume than with prostate size (all P < .0001). CONCLUSIONS PSA was significantly correlated with prostate size only in the largest prostate glands, but was significantly associated with tumor volume in small, medium, or large prostates. Thus, PSA continues to be a better marker for tumor volume than for prostate size.

Genetic Prostate Cancer Risk Assessment: Common Variants in 9 Genomic Regions are Associated with Cumulative Risk

PURPOSE Five genetic variants along chromosomes 8q24 and 17q have a cumulative association with prostate cancer risk. Our research group previously reported an association between these variants and clinicopathological characteristics. More recently 4 additional prostate cancer susceptibility variants were identified on chromosomes 2p15, 10q11, 11q13 and Xp11. We performed cumulative risk assessment incorporating all 9 genetic variants and determined the relationship of the new variants to clinicopathological tumor features. MATERIALS AND METHODS The genotype of 9 variants was determined in 687 men of European ancestry who underwent radical prostatectomy from 2002 to 2008 and in 777 healthy volunteer controls. We compared the incidence of these variants in prostate cancer cases and controls, and assessed their cumulative risk. We also determined the relationship of carrier status for the 4 new variants and clinicopathological tumor features. RESULTS Prostate cancer cases had an increased incidence of all 9 risk variants compared to controls. A cumulative model including the 9 single nucleotide polymorphisms provided greater prostate cancer risk stratification than a model restricted to the original 5 single nucleotide polymorphisms described. Specifically men with 6 or more variants were at greater than 6-fold increased risk for prostate cancer. Although 2p15 and 11q13 carriers were more likely to have aggressive features, other clinicopathological features were similar in carriers and noncarriers. CONCLUSIONS Genetic variants located in 9 regions have a cumulative association with prostate cancer risk. Identification of an increasing number of single nucleotide polymorphisms may provide greater understanding of their combined relationship with CaP risk and disease aggressiveness.