Maspin, a mammary serine protease inhibitor, was originally reported to be a tumor suppressor gene in breast and prostate cancers. The expression pattern of the maspin gene differs among cancer types and normal tissue however, and its significance as a tumor suppressor has been questioned. In this study, maspin expression and/or allele-specific methylation status were investigated in five melanoma cell lines and a normal human epidermal melanocyte (NHEM) cell line, and 80 surgically resected tumors (40 melanomas and 40 melanocytic nevi). One (HMV-I) of five melanoma cell lines overexpressed maspin protein whereas the remaining four melanoma cell lines and NHEM did not. The 19 CpG sites of the maspin promoter region were extensively hypomethylated in HMV-I, a maspin-positive cell line, and those of the remaining four melanoma and NHEM cell lines were hypermethylated. Furthermore, maspin-negative cell lines exhibited activation after treatment with 5-aza-2'-deoxycytidine, a DNA demethylating agent. Immunoreactivity for maspin was negative in normal skin melanocytes and 40 melanocytic nevi, but five (12.5%) of 40 melanomas were positive. The methylation status judged by the methylation-specific PCR method was inversely correlated with maspin protein expression in vitro and in vivo. These results suggest that maspin expression in normal skin melanocytes and melanocytic nevi may be repressed in a cell-type-specific manner, whereas maspin is expressed aberrantly in a subset of melanoma cells by epigenetic modification. Further investigations are required to determine the significance of aberrant maspin expression.

Cancer-associated DNA hypomethylation is as prevalent as cancer-linked hypermethylation, but the biological significance of DNA hypomethylation in carcinogenesis is less understood. The expression of Maspin (mammary serpin) in differentiated normal cells is regulated by epigenetic modifications in a cell-type-specific manner. Paradoxical Maspin expression due to epigenetic modification has been addressed in several cancer cell types. To elucidate the role of the Maspin gene in thyroid cancer, we studied methylation status in the promoter region and its expression in six human undifferentiated thyroid cancer cell lines and in specimens from 92 primary thyroid tumors, consisting of six follicular adenomas, 56 welldifferentiated thyroid cancers (WDTCs), 17 poorly differentiated thyroid cancers (PDTCs) and 13 undifferentiated thyroid cancers (UDTCs). Three of the six cell lines overexpressed Maspin mRNA and its protein product, but the remaining three did not. The methylation status at the promoter region was inversely correlated with Maspin expression. In Maspin-negative cell lines, Maspin expression was induced by treatment with 5-aza-2 0 -deoxycytidine, a DNA demethylating agent. Immunoreactivity for Maspin protein was frequently detected in UDTCs (8/13, 62%) and PDTCs (7/17, 41%). Immunoreactivity for Maspin was diffusely positive in UDTCs, and was restricted to dedifferentiated components of the tumor in PDTCs. Positive immunoreactivity was infrequent in WDTCs (1/56, 2%), and all follicular adenomas and normal thyroid glands were completely negative. Their methylation status evaluated by the methylation-specific PCR method showed a good inverse correlation with their immunoreactivity in surgically resected specimens. Our data suggest that overexpression of Maspin by DNA hypomethylation is closely associated with morphological dedifferentiation in thyroid cancers.

We examined expression of maspin and the epigenetic status of its gene in 40 primary hepato-biliary tract carcinomas and 11 cell lines originating from hepato-pancreatico-biliary tract carcinomas. Aberrant maspin expression was frequently observed immunohistochemically in biliary tract carcinomas (22/25, 88%) but not in hepatocellular carcinomas (HCCs) (0/15, 0%). Aberrant maspin expression by five pancreatico-biliary tract carcinoma cell lines was closely associated with demethylation at the maspin promoter. Five of six HCC cell lines were maspin-negative and exhibited extensive hypomethylation and hypoacetylation at the maspin promoter. Treatment with 5-aza-2'-deoxycytidine did not activate maspin expression in these five maspinnegative HCC cell lines, whereas treatment with Trichostatin A (TSA) activated maspin expression in two of them. Treatment with TSA increased histone acetylation in some HCC cell lines. These results suggest that aberrant maspin expression in biliary tract carcinomas is closely associated with demethylation at the promoter region, but that some HCC cell lines additionally require histone acetylation. In addition, the fact that maspinnegative HCC cell lines remain after treatment with TSA suggests the existence of other repressive factors controlling maspin expression.

We present a patient with primary CD30+ cutaneous T-cell lymphoma whose histological and clinical features overlapped with those of granulomatous slack skin disease (GSSD). A 26-year-old woman had infiltrative erythema on the abdominal wall and an incurable ulcerative lesion on the left knee. Her skin progressively became atrophic and pendulous, showing a hyperpigmented appearance over almost the whole body. Histopathologically, a dense lymphoid cell infiltrate accompanying numerous macrophages and multinucleated giant cells (MGC) extended into the subcutaneous tissue. Most lymphoid cells were small and positive for T-cell markers. Some relatively large atypical cells were scattered in the lesion, most of which (60%) were positive for CD30. T-cell receptor-beta gene rearrangement was confirmed in the abdominal lesion. MGC infiltrated more dominantly into a deeeper layer of the skin with the elastic fibres there almost completely disappearing. Immunoreactivity for CD30 of MGC was negative and overexpression of elastolytic metalloproteinases was observed. The association between primary cutaneous CD30+ lym- phoproliferative disorders and GSSD has not previously been reported. Overexpression of elastolytic metalloproteinases in MGC contributes to the disappearance of the elastic fibres and enhances the severity of the clinical course.

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