2012 | Abstract
Differential antigenic expression in colorectal cancer, mucosa adjacent to colorectal cancer, and normal colorectal mucosa.


Introduction:Despite of an excellent oncologic surgery with broad normal tissue margins, the mucosa next to the bed anastomosed is a frequent place of tumoral recurrence on colorectal cancer. Objective: This study was performed to evaluate the expression of mucins and carbohydrates associated antigens in normal mucosa colorectal specimens (NMC), mucosa adjacent to colorectal cancer (MACCR) and malignant colorectal tumour samples (CCR). Methods: Ninety colorectal cancer tumour samples and their MACCR, and also 68 NMC were included. Monoclonal antibodies (MAbs) against the following antigens were employed: anti-MUC1 (HMFG1), MUC2 (H-300) and MUC5AC (45M1), anti-Tn (HB-Tn1), Lex (KM380), sLex (KM93), Ley (C70) and sLea (1116-N5-19-9). An immunohistochemical approach following standard procedures was performed. Statistical analysis: an univariate statistical analysis with Chi2 was applied. Results: Malignant samples expressed MUC1 in 94% of cases, MUC2 in 52.4%, MUC5AC in 14.3%, Tn in 41%, Lex in 74.4%, sLex in 66.7%, Ley in 91.8% and sLea in 90.7%. Taking into account MUC2 and Ley expression, a positive correlation was found between MACCR and CCR: MUC2, P = .0006 and Ley, P = .0008. In malignant samples, MUC1 expression was increased compared to NMC (P = .04), also this mucin was 22.2% higher in MACCR than NMC. The expression of sLex and Ley was higher in CCR than NMC (179% and 33.6%, respectively). Expression of most antigens showed an increased tendency from NMC to MACCR and CCR: MUC1 (27.9%, 34.1% and 94%, respectively), Lex (60.9%, 30.5% and 74.4%, respectively), sLex (23.9%, 16.9% and 66.7%, respectively), Ley (68.7%, 78.3% and 91.8%, respectively) and sLea (62.1%, 45.6% and 90.7%, respectively). On the other hand, MUC5AC expression decreased in the mentioned sequence (51.5%, 20.7% and 14.3, respectively). Conclusion: Our results may support the hypothesis that the MACCR could be an intermediate point or “transitional zone” between NMC and CCR. Further studies are needed in order to correlate these findings with clinical outcomes.