Media type: E-Article Title: The predictive value of apoptosis protease‐activating factor 1 in rectal tumors treated with preoperative, high‐dose‐rate brachytherapy Contributor: Zlobec, Inti; Vuong, Te; Compton, Carolyn C. imprint: Wiley, 2006 Published in: Cancer Language: English DOI: 10.1002/cncr.21600 ISSN: 0008-543X; 1097-0142 Keywords: Cancer Research ; Oncology Origination: Footnote: Description: <jats:title>Abstract</jats:title><jats:sec><jats:title>BACKGROUND</jats:title><jats:p>The objective of this study was to assess the value of apoptosis protease‐activating factor 1 (APAF‐1) as a predictive marker of response in rectal tumors treated with preoperative, high‐dose‐rate endorectal brachytherapy.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>Immunohistochemistry for APAF‐1 was performed on 94 rectal tumor biopsy specimens from patients who were treated on a preoperative, high‐dose‐rate brachytherapy protocol. Tumors were considered positive when > 10% of tumor cells were immunoreactive. The association between APAF‐1 expression and tumor response was made using the chi‐square test.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Forty‐four tumors (43%) were positive for APAF‐1. Thirty tumors had complete pathologic tumor regression after preoperative radiotherapy. Of these, 18 tumors were positive for APAF‐1. A partial response occurred in 35 tumors. Eighteen tumors (51%) were positive for the protein. Only 8 of 29 nonresponsive tumors (28%) were immunoreactive for APAF‐1. A significant association was found between complete tumor regression and positive APAF‐1 status (<jats:italic>P</jats:italic> = 0.018). APAF‐1 expression in partially responsive tumors was significantly greater than in nonresponsive tumors (<jats:italic>P</jats:italic> = 0.03).</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>APAF‐1 expression in pretreatment rectal tumor biopsy specimens may be useful as a predictive marker of response to preoperative radiotherapy in patients with rectal carcinoma. Cancer 2006. © 2005 American Cancer Society.</jats:p></jats:sec> Access State: Open Access