CDKN1A and cancer: Interestingly, expression of certain SASP factors such as MMP3, together with the canonical senescence markers including p16INK4A and p21CIP1, was induced by MIT in both stromal and cancer cell populations, suggesting chemotherapy caused comprehensive in vivo senescence, although the SASP profile seemed to be differently developed between these two cell subpopulations (Figure 5d and Figure S6c).