The association with downstream activated proteins in the PI3K and or MAPK pathways was evaluated by using linear by linear tests. Recurrence free interval was de fined as the time from the date of first randomization until the occurrence of a local, regional, or distant recur rence or breast cancer specific death. selleck screening library Because a second ary contralateral breast tumor cannot be inferred from the molecular makeup of the primary tumor, whereas the other types of events can, in relation to tamoxifen resistance of the primary tumor, this was not considered an event, and these patients were censored at the date of their contralateral breast cancer. We hypothesized that the presence of a molecular al teration in the PI3K and or MAPK pathway is associated with tamoxifen resistance.

In our primary analysis, we tested the clinical validity of these molecular alterations as single markers, analyzed Inhibitors,Modulators,Libraries as binary factor. Covariate adjusted Cox proportional hazard regression analyses were performed, including an interaction variable. The following molecular alterations were tested PIK3CA mutation status, HER2, Inhibitors,Modulators,Libraries PTEN, and IGF 1R. In addition, we tested the interaction with tamoxifen for a composed variable, defined as any of these molecular alterations present versus no molecular alteration. Covariates included age, grade, tumor size, HER2 status, and PgR status. All sur vival analyses were stratified for nodal status. Because of multiple co primary end points, the level of signifi cance was set at 0. 01.

To assess the prognostic value of these molecular al terations, we analyzed their putative prognostic potential by using covariate adjusted Cox proportional hazard re gression analyses in the subgroup of patients who were randomized to the control arm. We did not use all pa tients and Inhibitors,Modulators,Libraries corrected for tamoxifen treatment because this correction would assume that all ER positive breast cancer patients would derive similar benefit from tam oxifen. Because the molecular alteration might be associ ated with tamoxifen resistance, simply correcting for the assumed tamoxifen benefit without a correction for a potential interaction between treatment and molecular alteration could bias the analysis for prognostic potential. This study complied with reporting recommendations for tumor marker prognostic studies criteria, as outlined in Additional file 1 Table S5.

Results Associations between molecular Inhibitors,Modulators,Libraries alterations in PI3K AKT mTOR pathway and known prognostic factors and downstream activated proteins Genotyping for PIK3CA exon 9 mutations was successful in 488 ER Inhibitors,Modulators,Libraries positive tumor samples. Exon 20 mutations could be assessed in 491 tumor samples. In total, 76 tumors harbored a PIK3CA exon 9 mutation. Mutations in exon 20 were found in 89 of the tumors. In total, four tumors exhibited Regorafenib both exon 9 and exon 20 mutations.