Pantuck, Allan J.

4521 Background: Expression of PDL1 by RCC has been associated with aggressive histology and poor survival. Tissue obtained from the patients enrolled in the IL-2 Select Trial, a prospective, single arm, multicenter CWG study, was analyzed by IHC to determine if PDL1or PDL3 expression predicted for response to initial or subsequent therapy. Methods: Paraffin embedded tumor tissue was stained for PDL1 and PDL3 expression, and results were correlated with RECIST defined response to IL2 treatment. Tumor tissue was considered positive for PDL1 if >5% of the tumor membranes stained for the marker. A cutoff of 10% was used for PDL3. Duration of subsequent VEGFR/mTOR inhibitor therapy was also correlated with tissue PDL1/3 expression. Results: 120 eligible pts were enrolled; 115 had clear cell histology. The overall response rate (ORR) to IL2 was 25% (30/120) with a median OS of 40.6 months. 113 tumors were stained. 18 (16%) were PDL1+. ORR was 19% and 50% in the patients PDL1- and PDL1+ tumors, respectively (p=0.012). 85 (75%) tumors were PDL3+. ORR was 10.7% and 29.4% in the PDL3- and PDL3+ tumors, respectively (p=0.075). In the 17 patients who were positive for both PDL1 and PDL3, ORR was 52.9%. In the 27 pts who were negative for both PDL1 and PDL3, ORR was 11.1%. 69 patients received at least 1 dose of a VEGFR TKI as next therapy following IL2 treatment. 66 tumors were stained. Pts who were PDL1+/PDL3+ had a shorter duration on VEGFR TKI therapy compared to pts who were PDL1-/PDL3- (see Table). Conclusions: This small, retrospective analysis suggests that PDL1 and PDL3 tissue expression may predict for better response to IL2. PDL1 expression has been suggested as a possible predictor of response to anti-PD1 therapy. The current data suggests that its expression may predict for benefit to other immune therapies. PDL3 (+/- PDL1) expression appears to correlate to less benefit from subsequent VEGFR TKI therapy. Funded by NCI SPORE Grant # 5 P50 CA101942-08. [Table: see text]

Chromophobe renal cell carcinoma (chRCC) typically shows ~7 chromosome losses (1, 2, 6, 10, 13, 17, and 21) and ~31 exonic somatic mutations, yet carries ~5%–10% metastatic incidence. Since extensive chromosomal losses can generate proteotoxic stress and compromise cellular proliferation, it is intriguing how chRCC, a tumor with extensive chromosome losses and a low number of somatic mutations, can develop lethal metastases. Genomic features distinguishing metastatic from nonmetastatic chRCC are unknown. An integrated approach, including whole-genome sequencing (WGS), targeted ultradeep cancer gene sequencing, and chromosome analyses (FACETS, OncoScan, and FISH), was performed on 79 chRCC patients including 38 metastatic (M-chRCC) cases. We demonstrate that TP53 mutations (58%), PTEN mutations (24%), and imbalanced chromosome duplication (ICD, duplication of ≥ 3 chromosomes) (25%) were enriched in M-chRCC. Reconstruction of the subclonal composition of paired primary-metastatic chRCC tumors supports the role of TP53 , PTEN , and ICD in metastatic evolution. Finally, the presence of these 3 genomic features in primary tumors of both The Cancer Genome Atlas kidney chromophobe (KICH) ( n = 64) and M-chRCC ( n = 35) cohorts was associated with worse survival. In summary, our study provides genomic insights into the metastatic progression of chRCC and identifies TP53 mutations, PTEN mutations, and ICD as high-risk features.

513 Background: Chromophobe renal cell carcinoma (chRCC) is the third most common histologic subtype of kidney cancer. While most of these tumors have an indolent behavior, 7% of patients with chRCC develop metastases, with no currently available standard of care. The Cancer Genome Atlas characterized chRCC, highlighting pathognomonic single copy chromosomal losses of 1, 2, 6, 10, 13 and 17, as well as a minimal mutation burden distinguishing it from all other cancer types. However, only 15% of the analyzed patients had advanced disease. We analyzed metastatic chRCC to further characterize these tumors and elucidate mechanisms leading to aggressive disease using a variety of next generation and whole genome sequencing. Methods: Our cohort of metastatic chRCC consisted of 40 patients with available clinical and pathologic data. Whole genome sequencing (WGS) was performed on 6 patients (4 primary tumors and 2 metastases), 42 additional samples from 33 patients were analyzed using targeted next-generation sequencing (MSK-IMPACT). Notably, we were able to collect and analyze matched primary and metastatic tumors from 7 patients. As control cohort 27 non-metastatic chRCC tumors were sequenced with MSK-IMPACT. Copy number patterns were computed with OncoSNP seq and FACETS. Results: The most commonly mutated genes in the aggressive chRCC tumors were TP53 and PTEN (WGS: TP53 67 %, PTEN 33%; MSK-IMPACT: TP53 61%, PTEN 27%). No other genes were mutated frequently. Primary tumor samples of chRCC did show the typical pattern of chromosomal losses in 1, 2, 6, 10, 13 and 17. Interestingly, these canonical losses could not be detected in the metastases even when accounting for tumor purity. Conclusions: TP53 and PTEN mutations are highly enriched in both primary and metastatic tumors of aggressive chRCC compared to the non-aggressive tumors and likely play a critical role in disease progression. More intriguingly, the observation of differential copy numbers in matched primary and metastatic tumors suggest whole genome or whole chromosome events in these samples. We are currently employing different bioinformatic and cytogenetic platforms to validate our novel hypothesis of chromosomal events as driver for metastatic development in chRCC.

Abstract Purpose: High-dose aldesleukin (HD IL2) received FDA approval for the treatment of metastatic renal cell carcinoma (MRCC) in 1992, producing a 14% objective response rate (ORR) and durable remissions. Retrospective studies suggested that clinical and pathologic features could predict for benefit. The Cytokine Working Group conducted this prospective trial to validate proposed predictive markers of response to HD IL2. Experimental Design: Standard HD IL2 was administered to prospectively evaluate whether the ORR of patients with mRCC with “good” predictive pathologic features based on an “integrated selection” model [ISM (e.g., clear-cell histology subclassification and carbonic anhydrase-9 (CA-9) IHC staining] was significantly higher than the ORR of a historical, unselected population. Archived tumor was collected for pathologic analysis including tumor programmed death-ligand 1 (PD-L1) expression. Results: One hundred and twenty eligible patients were enrolled between June 11 and September 7; 70% were Memorial Sloan Kettering Cancer Center (New York, NY) intermediate risk, 96% had clear cell RCC, and 99% had prior nephrectomy. The independently assessed ORR was 25% (30/120, 95% CI, 17.5%–33.7%, P = 0.0014; 3 complete responses, 27 partial responses) and was higher than a historical ORR. Thirteen patients (11%) remained progression free at 3 years and the median overall survival was 42.8 months. ORR was not statistically different by ISM classification (“good-risk” 23% vs. “poor-risk” 30%; P = 0.39). ORR was positively associated with tumor PD-L1 expression (P = 0.01) by IHC. Conclusions: In this prospective, biomarker validation study, HD IL2 produced durable remissions and prolonged survival in both “good” and “poor-risk” patients. The proposed ISM was unable to improve the selection criteria. Novel markers (e.g., tumor PD L1 expression) appeared useful, but require independent validation. Clin Cancer Res; 21(3); 561–8. ©2014 AACR.

Abstract Innovations and Challenges in Renal Cancer, chaired by Michael B. Atkins, was held April 28 to 29, 2006 in Cambridge, Massachusetts. The conference brought together leading experts in the fields of cancer research, medical oncology, urology, immunology, radiology, and immunotherapy, with the goal of advancing the field of renal cancer treatment by critiquing new data from ongoing clinical trials and stimulating communication among those involved in basic and clinical research. The conference proceedings published in this educational supplement to Clinical Cancer Research are intended to provide timely information and recommendations on important aspects of renal cancer genetics and biology and advances in prognostic classification and treatment.