title: E-cadherin downregulation at the infiltrating tumour front is associated with histological grade and stage in colorectal carcinoma of Malaysians.
abstract: Loss of E-cadherin, a 120 kDA transmembrane glycoprotein responsible for cell-cell adhesion, is one of the hallmarks of epithelial-mesenchymal-transition (EMT). E-cadherin expression was immunohistochemically studied in 94 histopathologically re-confirmed colorectal carcinomas (CRC) using a monoclonal antibody to E-cadherin (Dako: Clone NCH-38) on a Ventana Benchmark XT automated system. Each case was assessed for E-cadherin immunopositivity at two separate locations viz the tumour centre (TC) as well as the infiltrating front (IF). Expression was semiquantitated for proportion of immunopositive malignant cells as 0 (negative), 1 (1-25% staining), 2 (26-50% staining), 3 (51-75% staining) and 4 (>75% staining) and staining intensity: 0 (negative), 1 (weak), 2 (moderate) and 3 (strong). The final histoscore of E-cadherin immunopositivity was arbitrarily computed as proportion of immunopositivity multiplied by staining intensity of the malignant cells. E-cadherin histoscores were significantly lower at the IF (4.5±2.5) compared with TC (10.7±2.4). Furthermore, the histoscores were significantly reduced at the IF of 49 TNM III+IV tumours (3.6±2.5) compared with 45 II+III CRC (5.4±2.2). Reduction of E-cadherin expression was also noted in the 23 high grade (TC=8.6±3.2; IF=2.6±2.3) compared with 71 low grade tumours (TC=11.4±1.5; IF=5.1±2.3). E-cadherin is downregulated at the infiltrating front of CRC, possibly marking for EMT at this location. The downregulation is further enhanced amongst late stage and high grade tumours compared with earlier stage and low grade tumours; findings which are similar to that noted in CRC of other populations.
authors.affiliation: University of Malaya, Faculty of Medicine, Department of Pathology, 50603 Kuala Lumpur, Malaysia. cheahpl@ummc.edu.my.
authors.forename: Serena Diane
authors.initials: SD
authors.lastname: Dass
authors.forename: Phaik-Leng
authors.initials: PL
authors.lastname: Cheah
authors.forename: Diana Bee-Lan
authors.initials: DB
authors.lastname: Ong
authors.forename: Kean-Hooi
authors.initials: KH
authors.lastname: Teoh
authors.forename: Lai-Meng
authors.initials: LM
authors.lastname: Looi
mesh_terms: D015703:Antigens, CD; D014408:Biomarkers, Tumor / Q000032:analysis*; D001706:Biopsy; D015820:Cadherins / Q000032:analysis*; D002277:Carcinoma / Q000737:chemistry* / Q000556:secondary; D015179:Colorectal Neoplasms / Q000737:chemistry* / Q000473:pathology; D015536:Down-Regulation; D006801:Humans; D007150:Immunohistochemistry; D008296:Malaysia; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011237:Predictive Value of Tests
chemical_list: D015703:Antigens, CD; D014408:Biomarkers, Tumor; C513384:CDH1 protein, human; D015820:Cadherins