Fig. 5

Detection of micronuclei in biopsies of human ovarian cancer. a: Micronuclei-like structure (white arrows) labeled with 53BP1 in primary culture isolated from OC47 tissue (borderline serous cancer). DAPI staining of these cytoplasmic structures were invisible. b: Micronuclei (white arrows) marked with 53BP1 and γH2AX in primary culture from OC9. Note although the image capture for DAPI staining was over-exposed, it was still invisible at the position of 53BP1/γH2AX-positive compartment (white arrow). OC9: moderately differentiated serous cancer. c: Detection of MN-like structures in cryosections of human ovarian cancer double labeled with DAPI and phosphorylated TP53-pSerine15. White arrows indicate micronuclei. OC47: highly differentiated serous cancer. d: Schematic representation of DNA metabolism in IR-induced MN that potentially perturbs genomic stability. Unrepaired DSBs in mitoses trigger MN formation in post-mitotic cells. Interphase MN continue to process DNA fragments into ssDNA. During next mitosis, MN disintegrate and release existing ssDNA that admix with chromosomal DNA and promote chromosomal shattering or high-frequent rearrangement in next cell cycle, causing illegitimate re-integration of DNA fragment into the genome