CRC is a complex cancer type that takes place in the lower gastrointestinal tract (colon and rectum). The transformed cells therein are the glandular epithelial cells. CRC is divided into three classes: hereditary, sporadic, and colitis-associated. Plenty of risk factors account for the increased susceptibility to CRC with long-standing ulcerative colitis and Crohn’s disease with increasing age is the most important (Saraiva et al., 2023). The goal of this work is to identify and explore the DEGs in the EOCRC and LOCRC.
Upon shortlisting the DEGs and investigating the corresponding protein-protein interactions, ten hub genes were obtained, namely COL1A1, VWF, COL3A1, EGF, IGF1, COL1A2, ITGB3, COL11A2, COL6A1, CD163. The obtained hub genes were predicted to be regulated through several transcriptional factors including FOXC1, GATA2, YY1, TFAP2A and PPARG.
COL1A1 is a gene encoding for the alpha 1 chain of type I collagen forming the network of connective tissue as well as extracellular matrix. It has been recently many reports linked of COL1A1 to important processes such as cancer progression, wound healing, and tissue engineering (Barnes et al., 2019; Liu et al., 2021).
VWF gene encodes for von Willebrand factor, one of the key proteins involved in blood coagulation cascades. However, its role is not restricted in blood coagulation since the latest researches have focused on its participation in cardiovascular disease, with studies suggesting that elevated levels of VWF are associated with increased risk of thrombosis and heart disease (Favaloro et al., 2021; Kotronia et al., 2021).
COL3A1 (alpha 1 chain of type III collagen-encoding gene) which is distributed many tissues like skin and blood vessels, among other tissues. Recent studies have linked the role of COL3A1 differential expression in tissue repair, wound healing, and fibrosis (Qian et al., 2021; Wang et al., 2021).
EGF, on the other hand, encodes for epidermal growth factor, the prominent growth factor involved in the cellular growth, division and proliferation. As a consequence, it has been implicated in various types of cancer types as well as progression and therapy. Hence, numerous EGF receptor antagonists were FDA-approved as potential treatments for several types of cancer (Esmaeili et al., 2020; She et al., 2021).
Insulin-like growth factor 1 (IGF1), is a hormone that resembles insulin in its structure and the liberated connected peptide. Being a growth factors, it promotes growth and development of different tissues and wound healing. Therefore, there were multiple reports suggesting the association of IGF1 in crucial processes including aging, neurodegenerative diseases, and cancer. Also, IFG1 signaling interruption might halt disease progression (Feik et al., 2010; Guo et al., 2022).
It is obvious that six out of ten hub genes encode for collagen synthesis and assembly as confirmed by the gene enrichment results. This indicates the important role especially in EOCRC which is a prerequisite event during its metastasis considering its more aggressive than LOCRC. In other words, disorganized extracellular matrix, in which collagen is a mainstay, aids the disintegration of connected cells and, thus, facilitates metastatic invasion (Kaushik et al., 2019; Najafi et al., 2019). Additionally, two growth factors (EGF and IGF1) were in the ten hub genes differentially expressed in EOCRC and LOCRC. These factors promote the cellular growth, development and proliferation which may interpret their differential expression. Accordingly, many guided therapies have focused on these growth factors to block CRC (Gligorijević et al., 2022). About 25–82% of CRC cases exhibit EGF overexpression (Janani et al., 2022). It has been proved that VWF can mediate tumour cell adhesion to endothelial cells. Besides, it enhances platelets recruitment into the tumour microenvironment, where tumour-platelet aggregates aids in the spreading of cancer (Colonne et al., 2022).
Concerning survival rate of the obtained hub genes, EGF was the only one displaying good prognostic outcome. This is in an agreement with the previous reports of CRC (Schölch et al., 2019). Nonetheless, it failed to be predictive biomarker as resistance to multi-drug entities of CRC was well-established (J. Zhou et al., 2021). COL1A1, albeit predicted to be poor prognostic biomarker, is a potential predictive biomarker which needs further in-depth investigation.