<prompt> Ki 67 antigen is associated with carcinoma of:BreastStomachlungNone of the above  <response>: PCNA is a nuclear protein associated with a DNA polymerase whose expression increases in phase G1 of the cell cycle, reaches its maximum at the G1S interface, and then decreases through G2. Immunohistochemical staining for PCNA outlines the proliferating compaments in breast tissue. Good correlation is noted between PCNA expression and a cell-cycle distributions seen on flow cytometry based on DNA content, and b uptake of bromodeoxyuridine and the proliferation-associated Ki-67 antigen. Individual proliferation markers are associated with slightly different phases of the cell cycle and are not equivalent. PCNA and Ki-67 expression are positively correlated with p53 overexpression, high S-phase fraction, aneuploidy, high mitotic index, and high histologic grade in human breast cancer specimens, and are negatively correlated with estrogen receptor content. Ref: Schwazs principle of surgery 9th edition, chapter 17. 