The prognostic roles of PYCR2 and ZBTB18 expression in tissues of colorectal carcinoma and non-neoplastic tissues: an immunohistochemical study

ABSTRACT

Background: It is important to detect novel biomarkers responsible for the progression and spread of colorectal cancer (CRC) to better evaluate the prognosis of the patients, provide better management, and foster the development of therapeutic targets. In humans, pyrroline-5-carboxylate reductase 2 (PYCR2) is encoded on chromosome 1q42.12, and its metabolic activity has been linked to oncogenesis in many cancers. Zinc finger and broad-complex, tramtrack, and bric-à-brac (BTB) domain-containing protein 18 (ZBTB18), a zinc finger transcriptional repressor, has been found to have a tumor-suppressor role and to be methylated in CRCs. To date, the prognostic roles of PYCR2 and ZBTB18 in CRC patients have not been thoroughly studied. Objective: To evaluate the tissue protein expression of PYCR2 and ZBTB18 in CRC and adjacent non-neoplastic intestinal tissues, to detect their roles in CRC carcinogenesis, progression and metastases. Patients and methods: After applying the inclusion criteria, 60 CRC patients were included in the study. Tissue samples from the tumor and the adjacent non-neoplastic tissues were stained with PYCR2 and ZBTB18. The patients were followed up for about 30 months (range 10 to 36 months). We performed a correlation regarding the expression of the markers, and clinicopathological and prognostic parameters. Results Upregulation of PYCR2 and downregulation of ZBTB18 were found to be higher in CRC tissue than in the adjacent non-neoplastic colonic mucosa (p = 0.026 and p < 0.001 respectively). High expression of PYCR2 and low expression of ZBTB18 were positively correlated with large tumor size, higher tumor grade, advanced tumor stage, presence of spread to lymph nodes, and presence of distant metastases (p < 0.001). High PYCR2 and low ZBTB18 expressions were significantly associated with poor response to therapy (p = 0.008 and 0.0.17 respectively), as well as high incidence of progression and recurrence (p = 0.005), and unfavorable overall survival (OS) rates (p = 0.001). Conclusion: High expression of PYCR2 and low expression of ZBTB18 were independent predictors of CRC, progression, poor prognosis and unfavorable patient OS and progression-free survival (PFS) rates. (AU)