Immunohistochemical expression of the hepatocyte growth factor in chromophobe renal cell carcinoma.

BACKGROUND: The prognostic value of Hepatocyte growth factor (HGF) in non-clear cell renal cell carcinoma (RCC) is still unclear. The aim of this study is to evaluate the prognostic impact of HGF expression in a large cohort of chromophobe RCC (chRCC). METHODS: Patients who underwent renal surgery due to chRCC were recruited. Clinical data was retrospectively evaluated. Tumor specimen were analyzed for HGF expression by immunohistochemistry. RESULTS: 81 chRCC patients were eligible for analysis, thereof 37 (45.7%) patients were positive for HGF. No significant associations were found for HGF expression and clinical attributes in patients with chRCC. Kaplan-Meier analysis revealed no differences in 5-year overall survival (OS) for patients with HGF- compared to HGF+ tumors (95.0% versus 90.9%; p = 0.410). CONCLUSIONS: In chRCC HGF expression is not associated with parameters of aggressiveness or survival.

Growth Arrest-Specific 6 in Chromophobe Renal Cell Carcinoma.

BACKGROUND: Overexpression of tumor-associated growth arrest-specific protein 6 (Gas6) is found in many tumor entities. The prognostic value of Gas6 in renal cell carcinoma (RCC), especially in non-clear cell RCC, is still unclear. AIM: The aim of the study was to evaluate the prognostic impact of Gas6 expression in a large cohort of patients with chromophobe RCC (chRCC). MATERIAL AND METHODS: Patients who underwent renal surgery due to chRCC were retrospectively evaluated. Tumor specimens were analyzed for Gas6 expression by immunohistochemistry. RESULTS: Eighty-one chRCC patients were eligible for analysis; of these, 24 (29.6%) patients were positive for Gas6. No significant associations were found for Gas6 expression and clinical attributes in patients with chRCC. The Kaplan-Meier analysis revealed no differences in 5-year overall survival for Gas6- compared to Gas6+ (89.6% vs. 100.0%; p = 0.288) tumors. CONCLUSION: In chRCC, Gas6 expression is not associated with survival and other parameters of aggressiveness. Due to the rare incidence of chRCC, further studies with larger cohorts are warranted.

Trophoblast Cell Surface Antigen 2 (Trop2) in Chromophobe Renal Cell Carcinoma.

BACKGROUND: Overexpression of tumor-associated calcium signal transducer 2 (Trop2) is found in many tumor entities. The prognostic value of Trop2 in renal cell renal carcinoma (RCC), especially in nonclear cell RCC, is still unclear. AIM: The aim of this study was to evaluate the prognostic impact of Trop2 expression in a large cohort of patients with chromophobe (ch)RCC. MATERIALS AND METHODS: Patients who underwent renal surgery due to chRCC were retrospectively evaluated. Tumor specimens were analyzed for Trop2 expression by immunohistochemistry. RESULTS: Eighty-one chRCC patients were eligible for analysis, of these 24 (29.6%) patients were positive for Trop2. No significant associations were found for Trop2 expression and clinical attributes in patients with chRCC. The Kaplan-Meier analysis revealed no differences in 5-year overall survival for Trop2- compared to Trop2+ (89.6% vs. 100.0%; p = 0.288). CONCLUSION: In chRCC, Trop2 expression is not associated with survival and other parameters of aggressiveness. Due to the rare incidence of chRCC, further studies with larger cohorts are warranted.

PD-L2: A prognostic marker in chromophobe renal cell carcinoma?

In the context of cancer immunotherapy, PD-1 as well as PD-L1 has been widely studied in renal cell carcinoma (RCC). PD-1 and PD-L1 play a significant role as prognostic markers in clear cell renal cell carcinoma. In contrast, little is known about PD-L2 expression patterns in RCC, especially in rarer subtypes. The aim of this study was to evaluate the prevalence, distribution and prognostic impact of PD-L2 expression in chromophobe (ch)RCC. Eighty-one patients who underwent renal surgery due to chRCC were retrospectively evaluated. Tumor specimens were analyzed for PD-L2 expression by immunohistochemistry. Expression data were associated with clinicopathological parameters and overall survival (OS). Twenty-three (28.4%) patients showed a PD-L2 > median (PD-L2 high) staining intensity. No significant association between clinicopathological parameters and PD-L2 expression was identified. A significant difference between 5- and 10-year OS in dependence of PD-L2 expression was found (PD-L2 low 96.4 and 87.7% vs. PD-L2 high 87.1 and 56%; log rank, p = 0.029). However, in multivariate analysis PD-L2 expression failed to be proofed as an independent prognostic factor. In conclusion, to our knowledge this is the first study evaluating the prognostic impact of PD-L2 in a considerably large cohort of chRCC. Our results showed a significant diminished OS in dependence of PD-L2 expression. This implicates that PD-L2 might play a role as prognostic marker in chRCC demanding further evaluation.

c-Met in chromophobe renal cell carcinoma.

c-Met plays a role as a prognostic marker in clear cell renal cell carcinoma. In addition, recently the tyrosine kinase inhibitor cabozantinib targeting c-Met was approved for the treatment of advanced renal cell carcinoma (RCC). In contrast to clear cell RCC, little is known about c-Met expression patterns in rarer RCC subtypes. The aim of this study was to evaluate the prevalence, distribution and prognostic impact of c-Met expression on chromophobe (ch)RCC. Patients who underwent renal surgery due to chRCC were retrospectively evaluated. Tumor specimens were analyzed for c-Met expression by immunohistochemistry. Expression data were associated with clinicopathological parameters including patient survival. Eighty-one chRCC patients were eligible for analysis. Twenty-four (29.6%) patients showed a high c-Met expression (c-Methigh, staining intensity higher than median). Our results showed an association between c-Methigh expression and the existence of lymph node metastasis (p = 0.007). No further significant clinicopathological associations with c-Met were identified, also regarding c-Met expression and overall survival. In conclusion, to our knowledge this is the first study evaluating the prognostic impact of c-Met in a considerably large cohort of chRCC. High c-Met expression is associated with the occurrence of lymph node metastasis. This indicates that c-Met might be implicated into metastatic progression in chRCC.

PD-1/PD-L1 expression in chromophobe renal cell carcinoma: An immunological exception?

Immune checkpoint inhibitors targeting the inhibitory cross talk between tumor and immune cells have been approved for therapy in renal cell carcinoma (RCC). In contrast to clear cell RCC, little is known on PD-1/PD-L1 expression patterns in rarer RCC subtypes. The aim of this study was to evaluate the prevalence, distribution and prognostic impact of PD-1 and PD-L1 expression in chromophobe (ch)RCC. Patients who underwent renal surgery due to chRCC were retrospectively evaluated. Tumor specimen was analyzed for PD-1 and PD-L1 expression by immunohistochemistry. Expression data were correlated with clinic-pathological parameters including patient survival. Eighty-one chRCC patients were eligible for analysis, thereof 25 (30.9 %) and 11 (13.6 %) patients were positive for PD-1+ tumor-infiltrating mononuclear cells (TIMCs) and tumoral PD-L1+ expression, respectively. No significant associations were found for PD-1+ TIMC or tumoral PD-L1+ expression and clinical attributes. In addition, no differences in 5- and 10-year overall survival for PD-1- TIMC compared to PD-1+ TIMC (90.5 and 72.2 vs. 100 and 75 %; p = 0.41) and for PD-L1- tumors compared to PD-L1+ tumors (91.9 and 76.4 vs. 100 and 50 %; p = 0.48) were observed. In conclusion, to our knowledge this is the first study to evaluate the prognostic impact of PD-1 and PD-L1 in chRCC. PD-L1 does seem to be expressed in a minority of all chRCC, likewise only a minority of chRCC was infiltrated by PD-1-positive inflammatory cells. Neither PD-1+ TIMC nor tumoral PD-L1+ expression was associated with parameters of aggressiveness or survival.