During colorectal carcinogenesis, a spectrum of lesions is formed with different malignant potentials and ambiguous morphologic features. To identify novel biomarkers, we previously performed a bioinformatics study to detect differentially expressed genes between colorectal adenoma (CRA) and colorectal carcinoma (CRC). The present study validated the diagnostic and prognostic significance of 6 components of the extracellular matrix (ECM), identified in the previous bioinformatics analysis (DCN, EPHA4, FN1, SPARC, SPON2 and SPP1). A total of 60 formalin-fixed paraffin-embedded biopsy samples were included in the present study, from 40 patients with CRA, malignant polyps and CRC with and without lymph node metastases. qPCR results revealed differential expression among the groups for all genes, except for EPHA4. Their expression proportionally increased with the level of malignancy. Among them, SPARC, SPON2 and SPP1 were differentially expressed between CRA and malignant polyps. Immunohistochemistry analysis revealed that intensity of staining increased with the severity of lesions. The present results suggested that ECM related proteins may have an important role in the development of CRC, with a possible diagnostic use for differentiation among various lesions, such as between CRA and malignant polyps. However, no significant potential was detected for these genes to predict lymph node metastases in CRC.
MicroRNAs of the miR-200 family have been shown experimentally to regulate epithelialmesenchymal transition (EMT). Although EMT is the postulated mechanism of development and progression of colorectal cancer (CRC), there are still limited and controversial data on expression of miR-200 family and their target genes during CRC cancerogenesis. Our study included formalinfixed paraffin-embedded biopsy samples of 40 patients (10 adenomas and 30 cases of CRC with corresponding normal mucosa). Expression of miR-141, miR-200a/b/c and miR-429 and their target genes (CDKN1B, ONECUT2, PTPN13, RND3, SOX2, TGFB2 and ZEB2) was analysed using quantitative real-time PCR. Expression of E-cadherin was analysed using immunohistochemistry. All miRNAs were down-regulated and their target genes showed the opposite expression in CRC compared to adenoma. Down-regulation of the miR-200 family at the invasive front in comparison to the central part of tumour was observed as well as a correlation of expression of miR-200b, CDKN1B, ONECUT2 and ZEB2 expression to nodal metastases. Expression of the miR-200 family and SOX2 also correlated with E-cadherin staining. These results suggest that the miR-200 family and their target genes contribute to progression of adenoma to CRC, invasive properties and development of metastases. Our results strongly support the postulated hypotheses of partial EMT and intra-tumour heterogeneity during CRC cancerogenesis.
Colorectal cancer (CRC) is one of the most common cancers worldwide. Molecular pathways involved in CRC development include stepwise accumulation of mutations, epigenetic changes, and changes in gene expression, leading to uncontrolled cell division and an invasive phenotype. However, not all cases possess these changes suggesting that there should be undiscovered mechanisms for CRC development. We therefore investigated SULF1, previously identified as a CRC candidate gene using bioinformatics analysis. We included 65 biopsy samples from patients with adenoma, malignant adenoma, and CRC with and without nodal metastases. We examined expression of SULF1 using quantitative real-time polymerase chain reaction. Its expression progressively increased from adenoma, where it was down-regulated, to invasive CRC, where it was up-regulated. Our findings indicate an involvement of SULF1 in CRC carcinogenesis and progression.