Expression of heat shock protein 105 and 70 in malignant melanoma and benign melanocytic nevi.

Background: Heat shock proteins (HSPs) restore immature proteins or denatured proteins, thus protecting cells. Also, the expression of some HSPs is elevated substantially in malignant tumors, but the expression of HSPs in association with melanoma has yet to be studied. Therefore, we examined the expression patterns of HSP 70 and 105 in melanoma, benign melanocytic nevi and normal human skin.

Methods: Two specimens of malignant melanoma, two of benign melanocytic nevi and six of normal human skin were analyzed using Western blot analysis for expression of HSP 70 and 105. In another set, 16 specimens of malignant melanoma, 24 of benign melanocytic nevi and eight of normal human skin were analyzed for the expression of HSP 105 using immunohistochemical studies.

Results: The Western blot analysis showed that HSP 70 was overexpressed in all three types. But, the HSP 105 was hardly expressed in normal human skin and benign melanocytic nevi. However, in malignant melanoma, the HSP 105 was overexpressed, and immunohistochemical examination of HSP 105 showed a result similar to that of Western blot analysis.

Conclusions: In our study, HSP 105 is thought to be a more relevant tumor-associated antigen in malignant melanoma than is HSP 70.