The subcellular distribution of phosphorylated Y-box-binding protein-1 at S102 in colorectal cancer patients, stratified by KRAS mutational status and clinicopathological features.

Oncoprotein Y-box-binding protein-1 (YB-1) is involved in all cancer hallmarks. One of the most studied post-translational modifications of YB-1 is phosphorylation on Serine 102 (S102), which is involved in cancer progression. KRAS mutations are frequent, have been associated with poor prognosis and therapy resistance, and they are considered a major stimulator of S102 YB-1 in vitro. In this study, a relationship between S102 YB-1 phosphorylation in subcellular fractions and KRAS mutation was investigated in CRC tissues, and its association with clinicopathological parameters was analyzed. Immunohistochemistry on 36 patient samples and 5 normal tissue samples highlighted nuclear S102 YB-1 was specific to cancer tissues. Nuclear S102 YB-1 was expressed in 47.2% of tumor tissues, which was positively correlated with KRAS mutation (P = 0.017). There was no significant association between cytoplasmic S102 YB-1 with KRAS mutation status (P = 0.391). Further studies in larger cohorts are needed to validate the observed results. The significant association between S102 YB-1 in the nucleus and KRAS mutation may suggest YB-1 as an effective target to improve survival of CRC patients with KRAS-mutated tumors.