Analysis of 1,25-dihydroxyvitamin D(3) receptors (VDR) in basal cell carcinomas.

We have analyzed expression of 1,25-dihydroxyvitamin D(3) receptor (VDR) protein and mRNA in basal cell carcinomas (BCC) of human skin. VDR immunoreactivity in BCCs was compared with the staining pattern of the proliferation marker Ki-67 in the same tumors. Additionally, VDR staining was compared to staining pattern of apoptotic cells by terminal UTP nucleotide end labeling assay. Frozen sections of superficial type, nodular type, and fibrosing type BCCs were consistently immunoreactive for VDR (mAb 9A7gamma) with almost every tumor cell labeled (n = 15). In general, VDR staining was pronounced in peripheral tumor cells. VDR immunoreactivity was consistently stronger in tumor cells than in adjacent or unaffected epidermis. No visual correlation was found in BCCs comparing labeling patterns of Ki-67-positive or apoptotic cells and mAb 9A7gamma. VDR mRNA was increased in BCCs (n = 6) compared to normal human skin (n = 5), as revealed by reverse transcription-polymerase chain reaction analysis. Our findings indicate that VDR is strongly expressed in BCCs and may be involved in the growth regulation of this tumour, and VDR mRNA and protein are increased in BCCs as compared to normal human epidermis.