MUC5AC and melanoma: Aberrations detected included BRAF V600E mutation in melanomas, colon cancer and histiocytosis by primer extension assay, deletion and SNP in the EGFR gene from lung adenocarcinomas by Sanger cycle sequencing, G12D mutation in the KRAS gene from a metastatic colon cancer using primer extension assay, and a multiplex PCR-based assay for microsatellite instability test from a colon biopsy with clusters of signet ring cells in a pool of mucin.