Senescent
tumor cells are nonproliferating
tumor cells which are closely related to
cancer progression by secreting senescence-related molecules, called senescence-associated secreting phenotypes. Therefore, the presence of senescent
tumor cells is considered a prognostic factor in various
cancer types. Although senescence-associated β-
galactosidase staining is considered the best marker for detection of senescent
tumor cells, it can only be performed in fresh-frozen tissues. p16INK4A, a
cyclin-dependent inhibitor, has been used as an alternative marker to detect senescent
tumor cells in
formalin-fixed
paraffin-embedded tissues. However, other reliable markers to detect senescent
tumor cells is still lacking. In the present study, using public single-cell
RNA-sequencing data, we found that p15INK4B, a
cyclin-dependent kinase inhibitor, is a novel marker for detection of senescent
tumor cells. Moreover, p15INK4B expression was positively correlated with that of p16INK4A in
colorectal cancer tissues. In in vitro studies,
mRNA expression of p15INK4B was increased together with that of p16INK4A in H2O2- and
therapy-induced
cancer senescence models. However, the
mRNA level of p15INK4B did not increase in the oncogene-induced senescence model in primary colonic epithelial cells. In conclusion, p15INK4B is a potential alternative marker for detection of senescent
tumor cells together with conventional markers in advanced stages of
colorectal cancer.