Evaluation of the Prognostic Value of Four ECM-Associated Genes in Recurrence and Metastasis of Colorectal Cancer

Colorectal cancer is a significant public health issue due to its high incidence and high mortality rate, especially when diagnosed late. Identifying new biomarkers that can predict the diagnosis and prognosis of CRC is critical to reducing the mortality rate of the disease. This study tested the relationship of four extracellular matrix genes (COL1A1, COL5A1, THBS2 and FN1) with CRC prognosis at the mRNA and protein levels. Our previous studies identified these genes as candidate prognostic biomarkers for CRC. They were analysed in two cohorts: retrospective (130 CRC tumours and 70 healthy colon tissues) and prospective (160 paired tumours and normal tissues with 180 CRC serum samples). Accordingly, in the retrospective cohort, COL1A1 (p>0.0001), COL5A1 (p>0.0001), THBS2 (0.0001) and FN1 (0.001) were expressed at higher levels in tumours compared to controls by qRT-PCR and in metastatic cases compared to non-metastatic cases. In the same cohort, immunohistochemistry analysis showed that increasing protein levels of COL1A1 and FN1 correlated with mRNA levels. In addition, high COL1A1 mRNA levels were associated with OS (p>0.011), RFS (p>0.0001), and DMFS (p>0.0001), high COL5A1 mRNA levels were associated with OS (0.042), RFS (0.013), DMFS (p>0.003) and high FN1 levels were associated with DMFS (p>0.039). In the prospective cohort, COL1A1, COL5A1 and THBS2 were found to be higher in tumour tissue compared to matched normal tissue and in metastatic tumours compared to primary tumours by qRT-PCR in 160 tumours and matched normal tissues. In this cohort, FN1 levels were unexpectedly higher in normal tissues than in tumour tissues. In the prospective cohort, where 180 CRC serum samples were also tested by ELISA, COL1A1 (p>0.0001), COL5A1 (p>0.05), and THBS2 (p>0.05) levels were higher in metastatic cases than in the sera of non-metastatic cases. As a result, this study associated COL1A1, COL5A1 and THBS2 genes, which have different data on their prognostic effects in the literature, with poor prognosis of CRC at both mRNA and protein levels.