Demir, DParvizi, MPehlivanoglu, BErgin, EAyhan, SDoganavsargil, B2024-07-182024-07-182168-8184http://akademikarsiv.cbu.edu.tr:4000/handle/123456789/8279The epidermal growth factor receptor (EGFR) expression is considered to play an essential role in the pathogenesis of colorectal adenocarcinoma. This study assessed the expression and predictive/prognostic value of EGFR expression in pre -op biopsy and post -op resection specimens in patients receiving neoadjuvant radiotherapy/neoadjuvant chemoradiotherapy (NRT/NCRT). Thirty-four consecutive patients were included in this study. The association between the prognostic features and EGFR immunohistochemical expression was analyzed in pre- (n=34) and post -treatment (n=22) tissue samples in cases with available tissue blocks. Of 34, 23 (67.6%) were men. The median age was 60.50 +/- 10.69 (range, 31-84) years. EGFR expression was detected in 88.2% of biopsy specimens and in 91.2% of surgical specimens. There was only slight agreement between pre -op and post -op EGFR expression scores (kappa value 0.11). There was no significant correlation between pre -op and post -op EGFR expression scores (p>0.05). Although pre -op EGFR positivity and higher pre -op EGFR scores seemed to indicate a worse prognosis, this association between pre -op EGFR expression and overall survival (OS) or disease -specific survival (DSS) did not reach statistical significance (p>0.05). The only case with a post -op EGFR score of three who died of the disease experienced local recurrence and had distant metastasis. In conclusion, EGFR positivity in pre -op biopsy samples seems to be associated with shorter survival, and increased EGFR expression in post -treatment resection specimens predicts aggressive behavior in patients with rectal adenocarcinoma who received NRT/NCRT. However, due to the molecular heterogeneity, EGFR expression status should be evaluated in resection specimens rather than in pre -op biopsy samples for optimal prognosis prediction.EnglishRECTAL-CANCERPROTEIN OVEREXPRESSIONGENE AMPLIFICATIONCOLORECTAL-CANCERFOLLOW-UPEXPRESSIONCARCINOMASArticle