TP53 and breast carcinoma: As shown in Figure 6, ionizing radiation induced SIPS in 10%–50% of cells within cultures of the p53-mutant cell lines MDA-MB-435s (breast carcinoma), MDA-MB-231 (breast carcinoma), MDD2 (breast carcinoma), and SK-MEL-28 (malignant melanoma), but did not induce SIPS in the p53-null cell lines HeLa (cervical carcinoma) and SKOV3 (ovarian carcinoma).