Comparison between Substance P and Calcitonin Gene-Related Peptide and Their Receptors in Colorectal Adenocarcinoma

<b>Background:</b> Colorectal cancer is a major health problem that still causes many deaths worldwide. Neuropeptides, such as substance P and calcitonin gene-related peptide, play the neurotransmitter and neurohormone roles that increase tumor invasiveness and metastasis potential. This study aimed to see whether these neuropeptides and their receptors-neurokinin 1 receptor and calcitonin receptor-like receptor-correlate with the diagnosis stage, tumor differentiation grade, and different patient characteristics in colorectal cancer and also to compare them. <b>Methods:</b> We performed serum analyses of substance P and CGRP levels in patients with colorectal cancer and also the immunohistochemical analysis of their receptors in colorectal tumors and then correlated them with the disease stage and with different tumor characteristics. <b>Results:</b> We demonstrated that both substance P and calcitonin gene-related peptide had increased levels in colorectal cancer and that their levels correlated with the stage of the disease and with the tumor differentiation grade. We also demonstrated the correlation of NK-1R and CRLR higher immunohistochemical scores with advanced and poorly differentiated tumors. <b>Conclusions:</b> This study demonstrates that the neuropeptides SP and CGRP and their receptors NK-1R and CRLR could play a role in the pathogenesis of colorectal cancer, and they could be used as diagnostic and prognostic markers and could represent potential therapeutic targets.