T-cadherin appears to act as a
tumor-suppressor factor in various
cancers. Downregulation of
T-cadherin is caused by a combination of allelic loss and hypermethylation of the
T-cadherin promoter region and is related to
cancer invasion. To elucidate the molecular mechanism of invasiveness of
basal cell carcinoma of the skin,
T-cadherin expression was investigated in archival pathological tissue sections made up of normal counterparts of skin and various types of
basal cell carcinoma. Immunohistochemical staining showed that
T-cadherin was not expressed in 38 of 51 (75%)
basal cell carcinoma specimens, whereas normal counterparts of the skin appeared to express abundant
T-cadherin. Loss of heterozygosity in intron 1 of the
T-cadherin gene was found in four of 20 informative cases that did not express
T-cadherin. Aberrant methylation of the
T-cadherin promoter region also was found in six of 25
basal cell carcinomas by methylation-specific polymerase chain reaction. In contrast, no structural alternations were found in two loss of heterozygosity-positive
basal cell carcinomas on sequence analysis. These findings indicated that
T-cadherin expression was downregulated by a combination of allelic loss and aberrant methylation in
basal cell carcinoma of the skin. Loss of
T-cadherin expression might be related to the biological behavior of
basal cell carcinoma. In addition, results of the present study suggested that downregulation of
T-cadherin in various
cancers might be related to
tumor invasiveness rather than
metastasis, because
basal cell carcinoma of the skin principally lacks metastatic activity.