The absence of IL-6 expression in HT-29 and RKO tumor cells, in contrast to normal colonocytes, may reflect the fact that, in advanced stages of tumor development, IL-6 is primarily produced by cells within the tumor microenvironment and immune cell populations, rather than by the tumor cells themselves (Tong et al., 2022; Wang et al., 2024). The gene discussed is IL6; the disease is neoplasm.