Loss of heterozygosity of adenomatous polyposis coli gene in cutaneous tumors as determined by using polymerase chain reaction and paraffin section preparations

It has been suggested that an alteration in the adenomatous polyposis coli (APC) gene, which is a tumor suppressor gene, is one of the earlier events in carcinogenesis of some adenocarcinomas. We undertook this study to deter mine the prevalence of loss of heterozygosity (LOH) of the APC gene in seve ral kinds of cutaneous tumors. Fifty-seven unrelated Japanese patients were examined for analysis of the APC gene. The 57 cases consisted of extramamm ary Pager's disease, squamous cell carcinoma (SCC), eccrine poroma and poro carcinoma, metastatic tumor of rectal adenocarcinoma and malignant melanoma . DNA was extracted from the tumor and normal portions dissected from the f ormalin-fixed paraffin-embedding sections and amplified with the use of the PCR. The amplified DNA was examined for LOH in the APC gene. Seven samples of 32 heterozygous persons of APC gene (three out of seven eccrine poromas , two eccrine porocarcinomas and two metastatic tumors of rectal adenocarci noma) showed for LOH in the APC gene. None of the heterozygous samples from the extramammary Pagets disease (11), SCC (five) and melanoma (five) showe d LOH. These results suggest that tumor or tumor suppressor genes, other th an the APC gene, may be responsible for extramammary Pager's disease and SC C and that LOH involving APC may have some relevance to the formation and p rogression of eccrine tumors as in rectal tumors. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.