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TRPM1 and MITF expression in conjunctival melanocytic proliferations
Author(s) -
MOULIN AP,
ZOGRAFOS L
Publication year - 2011
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2011.4261.x
Subject(s) - microphthalmia associated transcription factor , melanoma , biology , medicine , cancer research , transcription factor , genetics , gene
Purpose Downregulation of TRPM1, a transient receptor potential cation channel, has been correlated with a higher metastatic risk in skin melanoma. The promoter of TRPM1 contains MITF binding sites and MITF regulates in vitro the transcription of TRPM1. We have showed a partial loss of TRPM1 mRNA expression in a limited number of conjunctival melanoma. The aim of this study was to further investigate TRPM1 and MITF expression in a broader panel of conjunctival melanocytic proliferations Methods Expression of MITF and TRPM1 was assessed by immunohistochemistry in 17 conjunctival naevi, 8 PAM (6 PAM with atypia) and 16 conjunctival melanoma. Statistical analysis was performed with JUMP 8,0 software. Results A complete preservation of both MITF and TRPM1 expression was identified in all the naevi and the PAM. A partial loss of TRPM1 expression was found in 44% of the conjunctival melanoma (2 cases with a scattered loss of expression and 5 cases with a regional loss of expression). There was a significant partial loss of TRPM1 expression in the melanoma group compared with the naevi group (p=0,0027) or with the PAM group (p=0,0331). A partial loss of MITF was identified in 50% of the melanoma with significant reduction compared with the naevi group (p=0,0005) or with the PAM group (p=0,0262). There was a significant correlation between partial loss of TRPM1 expression and partial loss of MITF expression (p<0,001). Conclusion We demonstrate a reduction of both MITF and TRPM1 expression in conjunctival melanoma compared with benign melanocytic lesions, suggesting that the loss of these proteins might be correlated with tumor progression. The concomitant partial reduction of expression of both genes is in concordance with the regulatory role of MITF on TRPM1 transcription.