Long-term Prognostic Significance of HSP-70, C-myc and HLA-DR Expression in Patients with Malignant Melanoma

Aim: 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.

Methods: 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.

Results: 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.

Conclusions: 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.