Cyclin D3 protein content in human renal cell carcinoma in relation to cyclin D1 and clinico-pathological parameters

Aberrations in the G1/S checkpoint are common in malignancies and are probably important for tumor development. Few G1/S studies have been performed on renal cell carcinoma (RCC) and therefore in this study the cyclin D3 protein content in 80 RCCs and that in 12 corresponding normal kidney cortex tissues are characterized using Western blotting. High cyclin D3 protein content was observed in 16% of the tumors and was significantly associated with aneuploidy, high TNM stage, high nuclear grade, high proliferation and young age. There was no association between tumor cyclin D3 and patient survival. The cyclin D3 overexpression was confirmed by immunohistochemical staining of 72 tumors, showing both nuclear and cytoplasmic localization of cyclin D3 in a fraction of the tumors. The cyclin D1 content has earlier been characterized in this tumor material and there was no relation between cyclin D1 and cyclin D3 protein expression. In summary, a fraction of the tumors overexpressed cyclin D3, supporting that various aberrations in the G1/S transition are implicated in RCCs.