Altered gene expression in skin melanomas is correlated with the level of skin infiltration and metastatic spreading

Background: In many tumors and also in melanomas a high expression of different growth factor receptors is sometimes present, and epidermal growth factor receptor (EGFr) and oncogene c-erbB2 are often involved. Recently a tumor suppressor gene, called MTS1, has been identified. MTS1 may have an important function in many tumors like those of the lung, breast, bone, ovary and skin melanomas. Objectives: In our study we analyzed the expression at mRNA level of EGFr, c-erbB2 and MTS1 in biopsied paraffin-embedded tissues of skin melanomas at different stages of Breslow and according to the presence or absence of metastatic spreading during follow-up. Methods: The relative quantitation of the mRNA was performed from histological sections cut from formalin-fixed and paraffin-embedded tissues after RT-PCR. Eighteen patients with melanoma were studied at mRNA expression level of EGF-receptor, c-erbB2 oncogene and MTS1 tumor suppressor gene. The expression has been correlated with the Breslow stage of skin infiltration and the presence of recurrences during the follow-up period. Results: The level of expression of EGFr was connected with the level of skin infiltration; in Breslow stages 1 and 2 the expression is low and dearly higher in Breslow 3. But a higher expression is not directly correlated with the presence of recurrences. On the other hand higher levels of c-erbB2 and MTS1 mRNA are related, particularly in stage 3 of skin infiltration melanomas, with absence of recurrences. In this case c- erbB2 seems to be a variable independent of Breslow stage. Conclusions: Our study suggests in a preliminary way that a high level of expression of c- erbB2 or MTS1 could be connected with infiltrative melanomas, Breslow stage 3, that do not tend to cause recurrences. On the other hand the EGFr expression is related to the stage of the skin infiltration of the tumors.