KRT5 and neoplasm: However, CK5/6 expression was not observed with any significant association with gender, family history, smoking, alcohol, tumor location, gross appearance, lymph node metastasis and TNM stage (P = 0.652, 0.671, 0.432, 0.382, 0.267, 0.350, 0.629, and 0.056, respectively, Table 4).