MS4A1 and metastatic melanoma: Analysis of publicly-available gene expression data extracted from human melanoma samples derived from Gene Expression Omnibus (GEO)11, 12, 13 further supports the expression of the genes for B cell markers MS4A1 (CD20) and CD22 and of the transiently-expressed SHM/CSR enzyme AICDA (AID) in normal skin, primary, and metastatic melanomas.