The Expression of Carbonic Anhydrase (CA) IX/XII and Lymph Node Metastasis in Early Breast Cancer

PURPOSE: The aim of study was to test by immunohistochemical (IHC) staining whether carbonic anhydrase (CA) 9 and 12 have an effect on sentinel lymph node (SLN) metastasis in early breast cancer and to find clinicopathologic factors associated with SLN metastasis. MATERIALS AND METHODS: Between June 2003 and June 2011, medical records of 470 patients diagnosedwith breast cancer with pT1-2, pN0-2, and M0 were reviewed. Of these 470, 314 patients who underwent SLN biopsy±axillary dissection were subjects of this study. Using tissue microarray, IHC staining for CA9 and CA12 was performed. Clinicopathologic factors such as patient age, tumour size, lymphatic invasion, hormone receptor status, and the Ki-67 labeling index were analysed together. RESULTS: The mean age of all patients was 51.7 years. The mean number of harvested SLN was 3.62, and 212 patients (67.5%) had negative SLN. Lymphatic invasion, the Ki-67 labelling index of primary tumours, and CA9 staining of stromal cells, were independent risk factors for SLN metastasis in the multivariate analysis. In 33 patients (10.5%) without the three risk factors, no patient had SLN metastasis. In 80 patients without lymphatic invasion of primary tumours or CA9 staining of stromal cells, only four patients (5%) had positive SLN. CONCLUSION: CA9 staining of stromal cells is an independent risk factor for SLN metastasis as well as lymphatic invasion and a low Ki-67 labelling index of primary tumours in patients with early breast cancer. IHC staining of primary tumours for CA12was not associatedwith SLN metastasis.