Can Triple Negative Breast Tumors Be Further Subdivided by Immunohistochemical Analysis of Expression of Protein Panels?
Serdar Balci, Cigdem Irkkan, Charles L Shapiro, Kay Huebner, Gulnur Guler. Yildirim Beyazit University, Ankara, Turkey; James Cancer Hospital and Ohio State University Comprehensive Cancer Center, Columbus, OH; Ohio State University Comprehensive Cancer Center, Columbus, OH
Background: Triple negative breast tumors (TNBC) are a morphologically and molecularly diverse group of neoplasms. Recently there have been efforts in the literature to define subgroups according to protein expression profiles. Herein, we report the morphological and immunohistochemical profile of our TNBC cohort in terms expression of androgen receptor, claudin, p63 and stem cell, DNA damage response, epithelial mesenchymal transition and basal markers.
Design: 162 triple negative breast tumors were reviewed morphologically and TMA sections containing 2 cores from each tumor were used for immunohistochemistry. Expression of individual proteins was not necessarily available for every case so the valid percentages are given for each protein.
Results: Morphologically 123 (75.9%) cases were diagnosed as infiltrative ductal NOS. Of the 162 tumors; 91 (56.2%) were positive for basal markers: (77 (47.5%) for EGFR, 28 (17.3%) for CK5/6); 33 (21.2%) were positive for AR. For DNA damage response proteins 148 tumors (91.4%) exhibited loss of Fhit, 152 (93.8%) loss of Wwox and 85 (52.5%) loss of BRCA1 expression; 88 (55.7%) were p53, 124 (89.2%) γH2AX and 82 (62.1%) pChk2 positive. 72 (48.6%) tumors were claudin 3 and 4 low. For stem cell markers: 60 (42.0%) had at least one CD44P24N (P: positive; N: negative) cell, 90 (62.9%) had at least one CD24P44N cell and 23 (16.1%) had at least one CD44P24P cell. Totally 62 (43.4%) tumors were CD44 positive. ALDH1 expression is observed in 15 (17.9%) cases. For epithelial-mesenchymal transition markers: 84 (55.6%) were AREB, 21 (13.7%) were ZEB2, 121 (79.1%) were SLUG and 125 (81.2%) were TGF positive. p63 was positive in 29 (18.6%) of cases. On determining if subgroups with related biomarker expression can be identified among TN tumors by clustering analysis; we noted that although there are many one to one correlations between proteins we could not identify specific subgroups with similar protein expression profiles.
Conclusions: According to our results, with the biomarkers that we used it was not possible to identify specific subgroups of TN tumors with specific marker expression profiles.
Tuesday, March 5, 2013 9:30 AM
Poster Session III # 2, Tuesday Morning