Ho, Thai H.

ABSTRACTPurposeWe aimed to explore the hypothesis that early subclinical cardiac chamber dysfunction secondary to tyrosine kinase inhibitors (TKIs) in patients with metastatic renal cell carcinoma could be signaled by abnormal cardiac mechanics demonstrated by velocity vector imaging.MethodsEchocardiographic images were acquired from the apical views in 23 metastatic renal cell carcinoma patients. All patients had baseline and at least a 3‐month follow‐up echocardiogram after receiving TKI therapy. Subendocardial borders of all the cardiac chambers were traced to obtain volumetric and deformation indices.ResultsMean age was 67 ± 9 years with 92% men. The right ventricle peak systolic global longitudinal strain (GLɛ) and strain rate were significantly lower after TKIs (−23.49 ± 5.1 versus −19.81 ± 5.5, p = 0.002 and −1.52 ± 0.52 versus −1.24 ± 0.35 p = 0.02, respectively). LV GLɛ was not statistically different. Volumetric and deformation indices showed a minimal decrease of the right atrium reservoir and conduit functions, and no significant changes of left atrial function.ConclusionsThe right heart exhibited greater strain changes than the left heart after TKI treatment. The implications of these findings and their potential significance warrant further work. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:221–230, 2016

Abstract Purpose: We examined the hypothesis that mutations in mTOR pathway genes are associated with response to rapalogs in metastatic renal cell carcinoma (mRCC). Experimental Design: We studied a cohort of mRCC patients who were treated with mTOR inhibitors with distinct clinical outcomes. Tumor DNA from 79 subjects was successfully analyzed for mutations using targeted next-generation sequencing of 560 cancer genes. Responders were defined as those with partial response (PR) by RECIST v1.0 or stable disease with any tumor shrinkage for 6 months or longer. Nonresponders were defined as those with disease progression during the first 3 months of therapy. Fisher exact test assessed the association between mutation status in mTOR pathway genes and treatment response. Results: Mutations in MTOR, TSC1, or TSC2 were more common in responders, 12 (28%) of 43, than nonresponders, 4 (11%) of 36 (P = 0.06). Mutations in TSC1 or TSC2 alone were also more common in responders, 9 (21%), than nonresponders, 2(6%), (P = 0.05). Furthermore, 5 (42%) of 12 subjects with PR had mutations in MTOR, TSC1, or TSC2 compared with 4 (11%) of 36 nonresponders (P = 0.03). Eight additional non-mTOR pathway genes were found to be mutated in at least 4 of 79 tumors (5%); none were associated positively with response. Conclusions: In this cohort of mRCC patients, mutations in MTOR, TSC1, or TSC2 were more common in patients who experienced clinical benefit from rapalogs than in those who progressed. However, a substantial fraction of responders (24 of 43, 56%) had no mTOR pathway mutation identified. Clin Cancer Res; 22(10); 2445–52. ©2016 AACR. See related commentary by Voss and Hsieh, p. 2320

Abstract Monoclonal antibodies that target the programmed death-1 (PD-1)–programmed death ligand-1 (PD-L1) axis have antitumor activity against multiple cancers. The presence of sarcomatoid differentiation in renal cell carcinoma (RCC) is associated with resistance to targeted therapy and poor responses to IL2 immunotherapy. Given the aggressive nature of RCC with sarcomatoid differentiation and the exclusion of sarcomatoid histology from metastatic RCC clinical trials, less is understood regarding selection of therapies. Here, we characterized the PD-1/PD-L1 axis in RCC with sarcomatoid differentiation. We directly compared two PD-L1 antibodies and found concordance of PD-L1 positivity in 89% of tested RCCs with sarcomatoid differentiation. Coexpression of PD-L1 on neoplastic cells and the presence of PD-1–positive tumor-infiltrating lymphocytes were identified in 50% (13 of 26) of RCCs with sarcomatoid differentiation. In contrast, only 1 of 29 clear cell RCCs (3%) had concurrent expression of PD-L1 and PD-1 (P = 0.002). Our study suggests that RCC with sarcomatoid differentiation may express PD-1/PD-L1 at a higher percentage than RCC without sarcomatoid differentiation, and patients with these tumors may be good candidates for treatment with anti–PD-1/PD-L1 therapies. Cancer Immunol Res; 3(12); 1303–7. ©2015 AACR.

Abstract Next-generation sequencing is now commonly applied to measure genomic modifications, providing the opportunity for a more accurate view of cancer progression. That being said, several challenges including tumor purity, heterogeneity and the broad set of cancer associated cellular functions, increase the difficulty of interpreting cancer genomes and make analyzing them distinct from analysis of germline diseases. The ability to detect low allelic mutations in the broad set of cancer-associated genes is critically important. To address these issues, we developed an extended cancer panel, a targeted enrichment sequencing platform that includes over 1,300 cancer genes and 200 miRNAs that improves coverage in traditionally difficult to sequence NGS regions. In this study, we apply an integrated RNA/DNA analysis approach as well as our extended cancer panel to explore mutations in metastatic renal cell carcinoma (RCC) tissue samples before and after treatment. Our goal with this study was to test the importance of integrating DNA and RNA analysis, which allows for detection of mutational events that cannot be observed by either method alone. With RNA analysis it is possible to detect gene fusion events, expression of small variants (SNVs/indels), and gene expression levels while DNA analysis allows for detection of loss of heterozygosity (LOH), copy number variants (CNVs), and small variants. By integrating both the RNA and DNA analysis, it is possible to identify unique variant classes, such as unexpressed variants, allele specific expression (ASE), effects of CNVs on gene expression levels, and how fusion gene integration sites affect CNVs. In our study, each variant class was interpreted pre- and post-treatment, allowing for optimal analysis of treatment effectiveness. By applying both our RNA/DNA integration approach and our extended cancer panel to investigate metastatic RCC samples, we were able to classify many genomic alterations that drive cancer progression. For example, we found that anywhere from 5% to 30% of small variant mutations in driver genes called in the DNA reside in genes that are unexpressed in the RNA. Likewise, we noted multiple cases of ASE, where high profile variants observed in DNA were entirely absent in the RNA despite high expression levels. Strong correlations between CNVs observed in DNA and gene expression changes found in RNA were also detected. We also observed that about half of the RCC samples we tested were biallelic for VHL mutations, suggesting inherited predisposition combined with second hit somatic mutations, facilitating cancer progression. This analysis demonstrates how combining an integrated RNA/DNA approach with a cancer focused augmented enrichment panel allows for detection of both low allelic representation variants and unique variant classes, both of which are critical for accurate interpretation of cancer samples. Citation Format: Sean M. Boyle, Michael J. Clark, Elena Helman, Alexander S. Parker, Thai Ho, Shujun Luo, Scott Kirk, Parin Sripakdeevong, Mirian Karbelashvili, Deanna M. Church, Michael Snyder, John West, Rich Chen. Integrating RNA/DNA analysis with a comprehensive cancer panel to improve interpretations of stage four metastatic renal cell carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3899. doi:10.1158/1538-7445.AM2015-3899

Abstract Background: Renal cell carcinoma (RCC) is the most common type of kidney cancer responsible for ∼80% of kidney cancer cases. Circulating tumor cells (CTCs) are emerging as an important prognostic and predictive biomarker in several types of metastatic cancers. However, methods for CTC detection that target only EpCAM and/or cytokeratin (CK) to enrich CTCs, may fail to recognize the CTCs in clear cell RCC (ccRCC) because ccRCC lacks expression of EpCAM. The objective of this study was to develop a new technology capable of detecting CTCs including those with a mesenchymal phenotype in metastatic RCC. Methods: Blood samples from patients affected by metastatic RCC were provided by Mayo Clinic Arizona and analyzed by Creatv MicroTech. CellSieveTM microfilters, which have 7 µm diameter pores in a uniform array, with 160,000 pores in a 9 mm diameter area, were used for separation of CTCs in the blood specimen. 7.5 mL of whole blood was diluted in the prefixation buffer and filtered through the microfilter. Clinical immunohistochemical markers for RCC such as CD10 and vimentin were used to identify candidate CTCs. The cells collected on the filter were fixed, permeabilized, and stained with DAPI and fluorescent antibodies specific to CD10, vimentin, and CD45. The assay protocol was developed using three RCC cell lines, 786-O, Caki-1, and Caki-2, and validated using blood samples from patients with metastatic RCC. Results: The capture efficiencies for 786-O, Caki-1, and Caki-2 cell lines were determined to be 98%, 98% and 97%, respectively. On-filter antibody staining revealed heterogeneous expressions of vimentin and CD10 in RCC cells. Patient samples were collected in duplicate CellSaveTM tubes and processed one day later. A CD10+/vimentin+/CD45- cell population was detected in blood samples with enumeration ranging from 4 to 86 cells/7.5 mL of blood. We found that the RCC CTC profile was distinct from other types of cancers. The typical CTCs display abnormal morphology, including large nuclei (typically 15-30 µm in size), irregular cell size and shape, and high nucleus-to-cytoplasm ratio. Although CD10 and vimentin antibodies have cross-reactivity with white blood cells (WBC), the CTCs could be distinguished from WBC based on morphology, cell size and CD45- staining. Conclusions: We demonstrated that the CellSieveTM microfiltration assay is a very simple and efficient method to isolate a CD10+/vimentin+/CD45- cell population from patients affected by metastatic ccRCC. Future studies include fluorescence in situ hybridization to confirm loss of 3p, a molecular event that occurs in >90% of ccRCC. We are also analyzing blood samples from patients treated with tyrosine kinase inhibitors to determine if cell enumeration is predictive of response to treatment. This technology might greatly facilitate detection of EpCAM negative ccRCC CTCs. The clinical significance of these unusual, large, rod-shaped, naked nuclei require further molecular characterization. Citation Format: Peixuan Zhu, Thai Ho, Erik P. Castle, Richard W. Joseph, Melissa L. Stanton, Shuhong Li, Daniel Adams, Olga V. Makarova, Platte T. Amstutz, Cha-Mei Tang. Isolation and identification of circulating tumor cells in renal cell carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3081. doi:10.1158/1538-7445.AM2014-3081

Abstract Purpose: The interaction of programmed death-1 ligand (PD-L1) with its receptor (PD-1) on T cells inactivates antitumor immune responses. PD-L1 expression has been associated with poor outcomes in renal cell carcinoma (RCC) but has not been investigated in advanced RCC patients receiving VEGF-targeted therapy. Experimental Design: Formalin-fixed paraffin-embedded specimens were collected at baseline from patients in the COMPARZ trial. Tumor cell PD-L1 expression by IHC was evaluated using H-score (HS). Dual PD-L1/CD68 staining was used to differentiate PD-L1 tumor expression from tumor-associated macrophages. Intratumor CD8-positive T cells were quantified morphometrically. Associations between biomarkers and survival were investigated using the log-rank test. Results: HS data were available from 453 of 1,110 patients. Sixty-four percent of patients had negative PD-L1 expression (HS = 0). Patients with HS > 55 (n = 59, 13%) had significantly shorter overall survival (OS) than those with HS ≤ 55 in both pazopanib and sunitinib arms (median 15.1 vs. 35.6 and 15.3 vs. 27.8 months, respectively, P = 0.03). In both arms, median OS was shortest in patients with HS > 55 and intratumor CD8-positive T-cell counts > 300 (9.6 and 11.9 months with pazopanib and sunitinib, respectively). Median OS in patients with HS ≤ 55 and CD8-positive T-cell counts ≤ 300 was 36.8 and 28.0 months with pazopanib and sunitinib, respectively. Progression-free survival results were similar to OS results. Conclusions: Increased tumor cell PD-L1, or PD-L1 plus tumor CD8-positive T-cell counts, were associated with shorter survival in patients with metastatic RCC receiving VEGF-targeted agents. These findings may have implications for future design of randomized clinical trials in advanced RCC. Clin Cancer Res; 21(5); 1071–7. ©2014 AACR.