Abstract: Objective To explore the predictive and prognostic value of MAPK biomarkers for HER-2 positive breast cancer patients with chemotherapy. Methods A total of 83 cases of HER-2 positive breast cancer patients treated were selected in hospital from May 2010 to May 2012. All patients received neoadjuvant chemotherapy and surgery. The levels of MAPK and MAPK pMAPK in cancer and its adjacent tissues were detected by immunohistochemical staining. MAPK and pMAPK mRNA expression was detected by RT-PCR. The correlation between age, operation method, clinical stage, menstruation, estrogen receptor, MAPK, pMAPK and chemotherapy efficacy was analyzed. Results The levels of MAPK and pMAPK mRNA and protein expression in cancer tissues were significantly higher than those in adjacent tissues (P<0.05). Eighty three cases of breast cancer included 15 of CR (18.1%), 45 of PR (54.2%), 22 of SD (26.5%), and 1 of PD (1.2%). Sixty patients (72.3%) showed their clinical effects. Patients with high levels of MAPK and pMAPK had a significantly low clinical efficacy compared with those with low levels of MAPK and pMAPK (P<0.05). Multivariate analysis showed that pMAPK and MAPK expression were independent risk factors in the efficacy of chemotherapy (all P<0.05). MAPK-positive patients with 3 years survival without recurrence accounted for 41.8%, while 60.7% of MAPK-negative patients had 3 years survival (χ2=11.037, P=0.000). In contrast, 39.1% of the patients with positive pMAPK had 3 years survival compared with those with negative pMAPK who had as high as 58.7% of 3 years survival (χ2=11.037, P=0.000). Conclusion MAPK and pMAPK can be used as markers in the patients with HER-2 positive breast cancer for evaluation of chemotherapy and survival prognosis.

Key words: Mitogen-activated protein kinase, Breast cancer, Human epithelial growth factor receptor-2, Prognosis