SP may promote the formation of activated epidermal growth factor receptor (EGFR) complexes after binding to NK-1R, inducing transactivation of EGFR, activating the MAPK pathway, and inducing the activation of ERK2 and deoxyribonucleic acid (DNA) synthesis, thereby promoting the progression of HB (Castagliuolo et al., 2000). This evidence concerns the gene TACR1 and hemoglobin measurement.