Long-term prognostic significance of HSP-70, c-myc and HLA-DR expression in patients with malignant melanoma

Use of molecular markers indicative of the tumour oncogenic potential and host response may enhance our prognostic information for more effective treatment of melanoma patients. The roles of HSP-70 protein, c-myc oncogene and HLA-DR antigen expression were examined in melanoma patients and related to prognostic factors, recurrence rate and long-term survival.

Forty patients with tumours thicker than 1 mm were included in this study. All had elective node dissection and were followed for at least 7 years. Twenty-two had microscopic nodal metastases. Both primary melanoma tumour and lymph nodes were examined for the immunohistochemical expression of HSP-70 protein, c-myc oncogene and HLA-DR antigen.

Eighteen patients had a recurrence (45%) and 23 patients survived overall (57.50%). Positive HSP-70 expression was observed in 52.50% of the primary melanomas and was associated with improved overall survival, especially in the patient group with tumours > or = 1.5 mm (70%vs 26.70%, P=0.0159). C-myc oncogene was overexpressed in 47.50% and HLA-DR antigen in 42.50% of the primary melanomas, but no correlation with survival was observed. The expression profile of these molecular markers in the primary tumour did not predict the status of regional nodes. HLA-DR expression in lymph nodes was observed exclusively in the nodal tissue surrounding the metastatic melanoma tumour in five patients.

The immunohistochemical expression profile of HSP-70 but not of c-myc oncogene or HLA-DR antigen in the primary melanoma tumour could be of certain value in the identification of patients with graver prognosis who may benefit from more aggressive therapeutic strategies.