Germline genetic variation in JAK2 as a prognostic marker in castration-resistant prostate cancer.

OBJECTIVES: To evaluate the prognostic significance of germline variation in candidate genes in patients with castration-resistant prostate cancer (CRPC). METHODS: Germline DNA was extracted from peripheral blood mononuclear cells of patients with CRPC enrolled in a clinically annotated registry. Fourteen candidate genes implicated in either initiation or progression of prostate cancer were tagged using single nucleotide polymorphisms (SNPs) from HapMap with a minor allele frequency of >5%. The primary endpoint was overall survival (OS), defined as time from development of CRPC to death. Principal component analysis was used for gene levels tests of significance. For SNP-level results the per allele hazard ratios (HRs) and 95% confidence intervals (CIs) under the additive allele model were estimated using Cox regression, adjusted for age at CRPC and Gleason score (GS). RESULTS: A total of 240 patients with CRPC were genotyped (14 genes; 84 SNPs). The median (range) age of the cohort was 69 (43-93) years. The GS distribution was 55% with GS ≥8, 32% with GS = 7 and 13% with GS <7 or unknown. The median (interquartile range) time from castration resistance to death for the cohort was 2.67 (1.6-4.07) years (144 deaths). At the gene level, a single gene, JAK2 was associated with OS (P < 0.01), and 11 of 18 JAK2 SNPs were individually associated with OS after adjustment for age and GS. A multivariate model consisting of age, GS, rs2149556 (HR 0.67; 95% CI 0.38-1.18) and rs4372063 (HR 2.17; 95% CI 1.25-3.76) was constructed to predict survival in patients with CRPC (concordance of 0.69, P < 3.2 × 10-9 ). CONCLUSIONS: Germline variation in the JAK2 gene was associated with survival in patients with CRPC and warrants further validation as a potential prognostic biomarker.

Common Genetic Variation in CYP17A1 and Response to Abiraterone Acetate in Patients with Metastatic Castration-Resistant Prostate Cancer.

Treatment with abiraterone acetate and prednisone (AA/P) prolongs survival in metastatic castration-resistant prostate cancer (mCRPC) patients. We evaluated the genetic variation in CYP17A1 as predictive of response to AA/P. A prospective collection of germline DNA prior to AA/P initiation and follow-up of a mCRPC cohort was performed. Five common single-nucleotide polymorphisms (SNPs) in CYP17A1 identified using a haplotype-based tagging algorithm were genotyped. Clinical outcomes included biochemical response and time to biochemical progression on AA/P. Logistic regression was used to assess the association between tag SNPs and biochemical response. Proportional hazards regression was used to assess the association between tag SNPs and time to biochemical progression. Odds or hazard ratio per minor allele were estimated and p-values below 0.05 were considered statistically significant. Germline DNA was successfully genotyped for four tag SNPs in 87 patients. The median age was 73 years (54-90); the median prostate-specific antigen was 66 ng/dL (0.1-99.9). A single SNP, rs2486758, was associated with lower odds of experiencing a biochemical response (Odds ratio 0.22, 95% confidence interval 0.07-0.63, p = 0.005) and a shorter time to biochemical progression (Hazard ratio 2.23, 95% confidence interval 1.39-3.56, p < 0.001). This tag SNP located in the promoter region of CYP17A1 will need further validation as a predictive biomarker for AA/P therapy.

A novel prognostic model for patients with sarcomatoid renal cell carcinoma.

OBJECTIVE: To demonstrate sarcomatoid differentiation is an independent prognostic feature for patients with grade 4 renal cell carcinoma (RCC) with or without distant metastases. To identify independent predictors of survival, evaluate the correlation between the amount of sarcomatoid differentiation and cancer-specific survival (CSS), and to design a multivariate prognostic model for patients with sarcomatoid RCC. PATIENTS AND METHODS: We used the Mayo Clinic Nephrectomy Registry to identify 204 post-nephrectomy patients with sarcomatoid-variant RCC, as well as 207 patients with unilateral grade 4 RCC without sarcomatoid features for comparison. All slides were reviewed by one pathologist. CSS was estimated using the Kaplan-Meier method. The associations of clinical and pathological features with death from RCC were evaluated using Cox proportional hazards regression models. RESULTS: For all patients with grade 4 RCC, the presence of sarcomatoid differentiation was associated with a 58% increased risk of death from RCC (P < 0.001). For patients with grade 4 non-metastatic (M0) RCC, the presence of sarcomatoid differentiation was associated with an 82% increased risk of death from RCC (P < 0.001). For patients with sarcomatoid RCC, the 2009 primary tumour classifications, presence of regional lymph nodes and distant metastases, coagulative tumour necrosis, and the amount of sarcomatoid differentiation were each significantly associated with death from RCC in a multivariate setting. After adjusting for other prognostic variables, each 10% increase in the amount of sarcomatoid differentiation was associated with a 6% increased risk of death from RCC (P = 0.028). Patients whose tumours contained ≥30% (median amount) sarcomatoid differentiation were 52% more likely to die from RCC compared with patients whose tumours contained <30% sarcomatoid differentiation (hazard ratio 1.52; P = 0.018). CONCLUSIONS: Among patients with grade 4 RCC, either with or without distant metastases at surgery, sarcomatoid differentiation is significantly associated with adverse survival in a multivariate setting. We also suggest for the first time that the percentage of sarcomatoid differentiation is an independent prognostic feature in a multivariate setting. The 2009 primary tumour classifications, regional lymph node status, the presence of distant metastases classifications, coagulative tumour necrosis, and the amount of sarcomatoid differentiation are independent predictors of survival for patients with sarcomatoid RCC.

Carbonic anhydrase IX (CAIX) is not an independent predictor of outcome in patients with clear cell renal cell carcinoma (ccRCC) after long-term follow-up.

OBJECTIVE: To evaluate carbonic anhydrase IX (CAIX) expression as an independent prognostic marker for clear cell renal cell carcinoma (ccRCC). With recent smaller studies showing conflicting results, we aimed to update our initial analysis in 2007 with an additional 5-year follow-up. PATIENTS AND METHODS: We provided long-term follow-up of the same cohort used in our 2007 study (730 patients with unilateral, sporadic ccRCC treated surgically between 1990 and 1999). Associations of CAIX expression with RCC death and distant metastases were evaluated using Cox proportional hazards regression models. RESULTS: CAIX was expressed in 708 (97.0%) of the specimens; 163 tumours (22.3%) had low (≤85%) expression and 567 (77.7%) high (>85%) expression. There were 483 deaths and 265 RCC-specific deaths. The median follow-up for the 247 patients still under observation was 13.8 years. Univariately, low CAIX expression was associated with an increased risk of RCC death vs high expression (hazard ratio 1.62; P < 0.001). Low CAIX expression was not statistically significantly associated with RCC death or distant metastases after adjusting for nuclear grade or coagulative tumour necrosis. CONCLUSION: After additional long-term follow-up of our large cohort, our results continue to suggest that CAIX is not an independent prognostic marker for ccRCC.

Lack of Caudal-Type Homeobox Transcription Factor 2 Expression as a Prognostic Biomarker in Metastatic Colorectal Cancer.

BACKGROUND: Although the lack of CDX2 expression has recently been proposed as a potential biomarker for a high risk of relapse in patients with stage II and III colon cancer after complete surgical resection, its prognostic role in metastatic colorectal cancer (CRC) remains unclear and warrants investigation. MATERIALS AND METHODS: We identified 145 patients treated at our institution from 2006 to 2016, including 66 patients with CDX2-negative metastatic CRC and a comparison cohort of 79 patients with CDX2-positive metastatic CRC. Overall survival (OS) and progression-free survival (PFS) for first-line systemic therapy were estimated using the Kaplan-Meier method. The associations of CDX2 expression with survival were evaluated using Cox proportional hazards regression models. RESULTS: The prevalence of absent CDX2 expression in our cohort was 5.6%. Patients with CDX2-negative metastatic CRC were significantly more likely to be female, and to have right-sided primary tumors, poorly differentiated histologic features, and distant lymph node metastasis. The median OS for patients with CDX2-negative and -positive metastatic CRC was 8 and 39 months, respectively (hazard ratio [HR], 4.04; 95% confidence interval [CI], 2.49-6.54; P < .0001). After adjusting for covariates in a multivariate model, the association of a lack of CDX2 expression and OS remained statistically significant (HR, 4.52; 95% CI, 2.50-8.17; P < .0001). In addition, the median PFS (3 vs. 10 months; HR, 2.23; 95% CI, 1.52-3.27; P < .0001) for first-line chemotherapy was significantly decreased in patients with CDX2-negative metastatic CRC. CONCLUSION: The results of the present study show that a lack of CDX2 expression in metastatic CRC is an adverse prognostic feature and a potential negative predictor of the response to chemotherapy.

Non-V600 BRAF Mutations Define a Clinically Distinct Molecular Subtype of Metastatic Colorectal Cancer.

Purpose Molecular diagnostic testing has become an integral part of the evaluation of patients with metastatic colorectal cancer (CRC). Expanded mutational testing, such as next-generation sequencing (NGS), often identifies mutations with unclear clinical or prognostic implications. One such example is BRAF mutations that occur outside of codon 600 (non-V600 BRAF mutations). Methods We conducted this multicenter, retrospective cohort study to characterize the clinical, pathologic, and survival implications of non-V600 BRAF mutations in metastatic CRC. We pooled patients in whom non-V600 BRAF mutations were identified from NGS databases at three large molecular genetics reference laboratories. Results A total of 9,643 patients with metastatic CRC underwent NGS testing. We identified 208 patients with non-V600 BRAF mutations, which occurred in 2.2% of all patients tested and accounted for 22% of all BRAF mutations identified. Cancers with non-V600 BRAF mutations, compared with cancers with V600E BRAF (V600E BRAF) mutations, were found in patients who were significantly younger (58 v 68 years, respectively), fewer female patients (46% v 65%, respectively), and patients who had fewer high-grade tumors (13% v 64%, respectively) or right-sided primary tumors (36% v 81%, respectively). Median overall survival was significantly longer in patients with non-V600 BRAF-mutant metastatic CRC compared with those with both V600E BRAF-mutant and wild-type BRAF metastatic CRC (60.7 v 11.4 v 43.0 months, respectively; P < .001). In multivariable analysis, non-V600 BRAF mutation was independently associated with improved overall survival (hazard ratio, 0.18; P < .001). Conclusion Non-V600 BRAF mutations occur in approximately 2.2% of patients with metastatic CRC and define a clinically distinct subtype of CRC with an excellent prognosis.

Impact of Rhabdoid Differentiation on Prognosis for Patients with Grade 4 Renal Cell Carcinoma.

Renal cell carcinoma (RCC) with rhabdoid differentiation is thought to portend a poor prognosis, similar to RCC with sarcomatoid differentiation. Both features are currently classified as grade 4 RCC based on the most recent International Society of Urological Pathology (ISUP) grading system. We reviewed a large series of patients with grade 4 RCC to determine the differential effects of rhabdoid and sarcomatoid differentiation on patient outcome. We identified 406 patients with ISUP grade 4 RCC including 111 (27%) with rhabdoid differentiation. In multivariable analysis of grade 4 RCC tumors, the presence of rhabdoid differentiation was not associated with death from RCC (hazard ratio [HR]: 0.95; p=0.75); in contrast, sarcomatoid differentiation was significantly associated with death from RCC (HR: 1.63; p<0.001). Patients with RCC with rhabdoid differentiation were significantly more likely to die of RCC than a comparison cohort of 1758 patients with grade 3 RCC (HR: 2.45; p<0.001). The novel findings of our study suggest that rhabdoid and sarcomatoid differentiation should not be grouped together when assessing risk in a patient with grade 4 RCC but support the notion that rhabdoid differentiation is appropriately placed in the ISUP grade 4 category.

Impact of BRAF mutation and BRAF inhibition on melanoma brain metastases.

The impact of BRAF mutations in metastatic melanoma on the incidence of brain metastases and melanoma prognosis and the effect of BRAF inhibitors on the incidence of brain metastases has not been defined. Therefore, a retrospective analysis of patients with metastatic melanoma treated at three institutions was carried out to examine the impact of BRAF mutations and a BRAF inhibitor, vemurafenib, on the incidence of brain metastases. A retrospective review of 436 records revealed no difference in the incidence of brain metastases between patients with BRAF-mutated tumors versus those without (incidence rate ratio=1.11, 95% confidence interval: 0.80-1.53; P=0.53). A lower incidence of brain metastases was observed in patients with BRAF-mutated tumors who took vemurafenib before the development of brain metastases versus those who did not (incidence rate ratio=0.51, 95% confidence interval: 0.30-0.86; P=0.009). Although treatment with vemurafenib led to improvement in extracranial disease control, it did not significantly affect progression of existing intracranial disease and survival in these patients (P=0.7). Although our previous preclinical data have indicated that penetration of vemurafenib into the brain is limited, our retrospective analysis showed that there was a lower incidence of brain metastases in patients with BRAF-mutated tumors who took vemurafenib before the diagnosis of brain metastases.