DETECTION OF BETA-HUMAN CHORIONIC-GONADOTROPIN MESSENGER-RNA AS A MARKER FOR CUTANEOUS MALIGNANT-MELANOMA

The beta chain of human chorionic gonadotropin (hCG) hormone is produc ed by fetal cells, gonadal cell tumors and several types of non-gonada l carcinoma. hCG is composed of an alpha and a beta chain, the latter of which can be used to distinguish the molecule from other related go nadotropin hormones. Detection of beta-hCG mRNA transcripts can be pot entially useful as a marker to identify tumor cells. We devised a high ly specific and sensitive assay to detect the atavistic expression of beta-hCG in cutaneous melanoma by RT-PCR. Twenty-four melanoma cell li nes and 43 melanoma biopsies were evaluated for beta-hCG mRNA expressi on. An RT-PCR assay was developed to specifically distinguish beta-hCG poly-A mRNA from other related gonadotropin beta chains. This was per formed by endonuclease digestion of a unique Sty 1 site in the beta ch ain, followed by Southern blot analysis with a beta-hCG cDNA probe. Of the 24 melanoma cell lines analyzed, 18 expressed beta-hCG mRNA. Anal ysis of melanoma biopsy specimens revealed beta-hCG mRNA expression in 17/25 melanoma-positive TDLN, and in only 5/15 non-lymphoid melanoma metastases. beta-hCG mRNA expression had a 53% correlation to tyrosina se mRNA, a predominant melanoma marker. beta-hCG mRNA was not detected in normal donor PBL and normal lymph nodes. Detection of beta-hCG mRN A expression may be a useful molecular marker to define a subset of ma lignant melanoma. (C) 1996 Wiley-Liss, Inc.