KRT5 and neoplasm: Several studies have tried to identify novel diagnostic biomarkers for the management of MM patients, however, the currently available diagnostic strategies, mainly based on the evaluation of tumor biomarkers such as calretinin, cytokeratin 5, podoplanin, mesothelin, osteopontin, hyaluronic acid, fibulin-3 [28], vascular endothelium growth factor [30], aquaporin-1 [29], high mobility group box 1 [31], and macroH2A.1 [32], often fail to correctly diagnose MM due to the low rates of sensitivity and specificity of these biomarkers.