e15083 Background: In a variety of malignant diseases certain malignant markers either predict treatment response towards systemic therapies or have a prognostic impact for cancer patients. While a variety of such actionable as well as treatable targets have been characterized, although only in certain cancers, in renal cell cancer (RCC) no prognostic markers have so far been identified. Thus, grading according to the S.A. Fuhrman grading system from 1982 is the only prognostic feature and currently widely considered for treatment assessment. Methods: Paraffin-embedded tumor tissue sections derived from clear cell RCCs were immuno-histochemically analyzed for expression of embryonic transmembrane antigen CD98hc (SLC3A2). Expression levels were semi-quantitative analyzed and results were correlated with grade of differentiation, using the widely accepted Fuhrman classification. Results: We found that grade of malignancy of ccRCCs were directly correlated with high CD98hc expression levels. Semi-quantivative analyses revealed that 0 % (0/2) of grade 1 ccRCC, 70.0 % of grade 2 ccRCC (14/20), 86.6 % of grade 3 (26/30) and 100 % of grade 4 (10/10) were CD98hc positive. (p < 0.01, Qui-Quadrat Pearson test, n = 62). In contrast, tumor stage as determined by the WHO TNM system did not correlate with CD98hc levels (p > 0.05). Conclusions: From these data, we conclude that CD98hc is expressed in RCCs, whereby the extent of expression is likely to correlate directly with grade of malignancy. In ccRCCs, CD98hc might represent a novel and reliable marker for more aggressive and less differentiated subtypes.
Exposure‐toxicity relationship of cabozantinib in patients with renal cell cancer and salivary gland cancer
