KDF1 and cancer: Considering that genetic background differences in different patients may affect KDF1 expression, which may interfere with our observations of the pathological significance of KDF1 expression levels, we further compared the expression levels of KDF1 in cancer cells and paired adjacent non-neoplastic lung epithelial cells; and based on whether KDF1 levels were higher in cancer cells than in adjacent non-neoplastic lung epithelial cells, patients were divided into KDF1-increasing group and KDF1-non-increasing groups.