RUNX2 expression in conjunctival melanocytic proliferations

Abstract

AbstractPurpose Amplification of RUNX2 (6p21.2), a transcription factor involved in bone formation and in tumor progression of prostate and breast cancer, has previously been identified in 76% (16/21) of primary conjunctival melanoma and in 100% (4/4) of metastatic conjunctival melanoma. The aim of this study was to investigate RUNX2 expression at the protein level in a panel of conjunctival melanocytic proliferationsMethods Expression of RUNX2 was assessed by immunohistochemistry in 26 conjunctival naevi (14 compound naevi, 11 subepithelial naevi and 1 cellular blue naevus), 13 PAM (9 PAM with atypia) and 25 conjunctival melanoma. Statistical analysis was performed with JUMP 8,0 software. Expression was regarded as negative if less than 10% of the tumor cells expressed RUNX2. Examination was independently assessed by two observers.Results RUNX2 was found in 3 naevi (11,5 %), in one PAM with atypia (7,6%) and in 5 melanoma (20 %) without significant variation between the 3 groups. In the melanoma group, there was no correlation between RUNX2 expression and TNM category, depth of invasion, proliferation index (Ki67), local lymphatic invasion and the presence of metastasis. There was however a significant correlation between RUNX2 expression and death (p=0,0191).Conclusion RUNX2 is expressed in a limited number of conjunctival melanocytic proliferations without significant differential expression between benign and malignant lesions. The biological significance of RUNX2 in conjunctival melanoma tumor progression requires further functional investigations.