Association of ki67 and tumor marker p53 in locally advanced breast cancer patients and evaluation of response to neoadjuvant chemotherapy: a survey in South Iran

PURPOSE: Heterogeneity of breast cancer, the most common cancer in women, complicates approach to its treatment. Neoadjuvant chemotherapy (NAC) in the treatment of locally advanced breast cancer (LABC) with the endpoint of achieving pathologic complete response (pCR) is not always successful. The purpose of this study was to evaluate the clinicopathologic characteristics, biomarker status and response of LABCs to NAC. PATIENTS AND METHODS: Core biopsies and post-surgical specimens of LABC patients were evaluated after receiving NAC. Their lymph node involvement, tumor staging, grading, size, tumoral and stromal lymphocytic infiltration (TLI, SLI), hormonal status, ki67, p53 and HER2 expression were evaluated. Response to NAC was assessed using pCR, Miller-Payne grading and residual cancer burden. RESULTS: In a total of 71 patients, pCR rate was 5.6%. Strong association was observed between ki67 positivity and p53 expression (P-value˂0.001). Also ki67, TLI and SLI showed association with triple negative tumor subtype (P-value 0.011, 0.002 and 0.014). Good response to NAC was associated with p53 expression. Nodal metastatic residue was also associated with primary tumor’s nuclear grade. CONCLUSION: Strong correlation of ki67 and p53 can suggest probable interchangeability of both markers in the prognosis of LABC. In this study p53 even showed superiority to ki67 having association with good response. Strong association of ki67, TLI and SLI with triple negative tumor subtype can be parallel to an overall better response rate of this subtype. We can also propose the effectiveness of defining nuclear grade as a prognostic factor towards residual lymph node involvement post NAC.