RESUMO
OBJECTIVE: The study aimed to delineate the gene expression profile of LGR5, HES1 and ATOH1 in young Egyptian rectal cancer (RC) patients and investigate the correlation between expression profiles and clinical outcome. METHODS: The study was conducted on 30 young Egyptian RC patients. Expression study of LGR5, HES1 and ATOH1 were performed by quantitative PCR (QPCR) based on comparative Cq method after normalization to adjacent non tumor tissues and ACTB as a reference gene. Patients were followed up for assessment of response to neoadjuvant chemoradiotherapy (CRT) based on revised RECIST1.1. RESULT: The study detected overexpression of LGR5 and HES1 and down-regulation of ATOH1 in human RC tissues compared to non- tumor tissues. High expression of LGR5 was correlated with more depth of tumor invasion, lymph node (LN) metastasis, advanced cTNM stage and mesorectal fascia (MRF) involvement. More prominently, high LGR5 expression level was associated with poor response to CRT. LGR5 was suggested as unfavorable prognostic biomarker for RC. Conversely, HES1 and ATOH1 expression did not show significant association with most of the studied clinical criteria nor response to CRT. Still, HES1 and ATOH1 were significantly and inversely associated with presence of mucinous component. CONCLUSION: High LGR5 expression is indicative of poor prognosis among young Egyptian RC patients and is proposed as a predictive marker of resistance to neoadjuvant CRT. However, HES1 and ATOH1 expressions were not prognostic nor predictive of response to CRT. Overall, LGR5, HES1 and ATOH1 gene expression patterns among young onset RC patients, are in line with patterns encountered in older age groups.