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ABSTRACT: Purpose
This study investigated the association between tumor MYC protein expression and disease-free survival (DFS) of patients randomized to receive chemotherapy alone (Arm A) or chemotherapy with sequential (Arm B) or concurrent trastuzumab (Arm C) in the N9831 (Alliance) adjuvant HER2(+) trastuzumab breast cancer trial.Experimental design
This analysis included 1,736 patients randomized to Arms A, B, and C on N9831. Nuclear MYC protein expression was determined in tissue microarray sections containing three biopsies per patient or whole tissue sections using standard immunohistochemistry (clone 9E10). A tumor was considered positive for MYC protein overexpression (MYC(+)) if the nuclear 3+ staining percentage was more than 30%.Results
Five hundred and seventy-four (33%) tumors were MYC(+). MYC(+) was associated with hormone receptor positivity (χ(2), P = 0.006), tumors 2 cm or more (χ(2), P = 0.02), and a higher rate of nodal positivity (χ(2), P < 0.001). HRs for DFS (median follow-up: 6.1 years) for Arm C versus A were 0.52 (P = 0.006) and 0.65 (P = 0.006) for patients with MYC(+) and MYC(-) tumors, respectively (P(interaction) = 0.40). For Arm B versus A, HRs for patients with MYC(+) and MYC(-) tumors were 0.79 (P = 0.21) and 0.74 (P = 0.04), respectively (P(interaction) = 0.71). For Arm C versus B, HRs for patients with MYC(+) and MYC(-) tumors were 0.56 (P = 0.02) and 0.89 (P = 0.49), respectively (P(interaction) = 0.17).Conclusions
Our data do not support an impact of tumor MYC protein expression on differential benefit from adjuvant trastuzumab.
SUBMITTER: Dueck AC
PROVIDER: S-EPMC3805021 | biostudies-literature | 2013 Oct
REPOSITORIES: biostudies-literature
Dueck Amylou C AC Reinholz Monica M MM Geiger Xochiquetzal J XJ Tenner Kathleen K Ballman Karla K Jenkins Robert B RB Riehle Darren D Chen Beiyun B McCullough Ann E AE Davidson Nancy E NE Martino Silvana S Sledge George W GW Kaufman Peter A PA Kutteh Leila A LA Gralow Julie J Harris Lyndsay N LN Ingle James N JN Lingle Wilma L WL Perez Edith A EA
Clinical cancer research : an official journal of the American Association for Cancer Research 20130821 20
<h4>Purpose</h4>This study investigated the association between tumor MYC protein expression and disease-free survival (DFS) of patients randomized to receive chemotherapy alone (Arm A) or chemotherapy with sequential (Arm B) or concurrent trastuzumab (Arm C) in the N9831 (Alliance) adjuvant HER2(+) trastuzumab breast cancer trial.<h4>Experimental design</h4>This analysis included 1,736 patients randomized to Arms A, B, and C on N9831. Nuclear MYC protein expression was determined in tissue micr ...[more]