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.