The purpose of the present study was to investigate the association of glutathione S-transferase P1 (GSTP1) expression with resistance to neoadjuvant paclitaxel followed by 5-fluorouracil/ epirubicin/cyclophosphamide (P-FEC) in human breast cancers. The relationship of GSTP1 expression and GSTP1 promoter hypermethylation with intrinsic subtypes was also investigated. In this study, primary breast cancer patients (n = 123, stage II-III) treated with neoadjuvant P-FEC were analyzed. Tumor samples were obtained by vacuum-assisted core biopsy before P-FEC. GSTP1 expression was determined using immunohistochemistry, GSTP1 promoter methylation index (MI) using bisulfite methylation assay and intrinsic subtypes using DNA microarray. The pathological complete response (pCR) rate was significantly higher in GSTP1-negative tumors (80.0%) than GSTP1-positive tumors (30.6%) (P = 0.009) among estrogen receptor (ER)-negative tumors but not among ER-positive tumors (P = 0.267). Multivariate analysis showed that GSTP1 was the only predictive factor for pCR (P = 0.013) among ER-negative tumors. Luminal A, luminal B and HER2-enriched tumors showed a significantly lower GSTP1 positivity than basal-like tumors (P = 0.002, P < 0.001 and P = 0.009, respectively), while luminal A, luminal B and HER2-enriched tumors showed a higher GSTP1 MI than basal-like tumors (P = 0.076, P < 0.001 and P < 0.001, respectively). In conclusion, these results suggest the possibility that GSTP1 expression can predict pathological response to P-FEC in ER-negative tumors but not in ER-positive tumors. Additionally, GSTP1 promoter hypermethylation might be implicated more importantly in the pathogenesis of luminal A, luminal B and HER2-enriched tumors than basal-like tumors. (Cancer Sci 2012; 103: 913-920) N eoadjuvant chemotherapy (NAC) for primary breast cancer patients is known to enhance the operability of patients with advanced tumors previously considered inoperable, as well as making breast-conserving surgery more feasible for patients for whom such surgery was previously not feasible due to large tumor size. In addition, it is well established that patients who show a pathological complete response (pCR) to NAC can have a better prognosis than those who do not, (1)(2)(3) so the response to NAC can provide valuable information regarding patient prognosis. These advantages of NAC have led to its widespread use including recently for a growing number of breast cancer patients. However, pCR rates for NAC of only 20-30% of patients are still rather low. (4) Because adverse effects of various degrees of severity are seen in virtually all patients, it seems to be very important to develop predictive factors for the response to NAC to avoid the unnecessary use of NAC for patients who are unlikely to derive benefits from such therapy.Among predictive factors, estrogen receptor (ER), progesterone receptor (PR), HER2, histological grade (HG) and Ki-67 have been most extensively studied and significant associations of ER negativity, PR negativity, HER2 amp...

Aberrant promoter methylation of genes is a common molecular event in breast cancer. Thus, DNA methylation analysis is expected to be a new tool for cancer diagnosis. In this article, we have established a new, high-performance DNA methylation assay, the one-step methylation-specific polymerase chain reaction (OS-MSP) assay, which is optimized for analyzing gene methylation in serum DNA. The OS-MSP assay is designed to detect aberrant promoter methylation of GSTP1, RASSF1A, and RARβ2 genes in serum DNA. Moreover, two quality control markers were designed for monitoring the bisulfite conversion efficiency and measuring the DNA content in the serum. Serum samples were collected from patients with primary (n = 101, stages I-III) and metastatic breast cancers (n = 58) as well as from healthy controls (n = 87). If methylation of at least one of the three genes was observed, the OS-MSP assay was considered positive. The sensitivity of this assay was significantly higher than that of the assay involving conventional tumor markers (CEA and/or CA15-3) for stages I (24 vs. 8%) and II (26 vs. 8%) breast cancer and similar to that of the assay involving the conventional tumor markers for stage III (18 vs. 19%) and metastatic breast cancers (55 vs. 59%). The results of the OS-MSP assay and those of the assay involving CEA and/or CA15-3 seemed to compensate for each other because sensitivity of these assays increased to 78% when used in combination for metastatic breast cancer. In conclusion, we have developed a new OS-MSP assay with improved sensitivity and convenience; thus, this assay is more suitable for detecting aberrant promoter methylation in serum DNA. Moreover, the combination of the OS-MSP assay and the assay involving CEA and/or CA15-3 is promising for enhancing the sensitivity of diagnosis of metastatic breast cancer.

The aim of this prospective study was to evaluate the feasibility of periareolar injection of the contrast agent Sonazoid (SNZ) followed by ultrasonography (US) for the identification of sentinel lymph node (SLN) in breast cancer patients with clinically negative node. Patients (n = 100) with T1‐2N0M0 breast cancer received a periareolar injection of SNZ followed by US to identify contrast‐enhanced SLN. Each contrast‐enhanced SLN underwent fine needle aspiration cytology (FNAC) followed by SLN biopsy with a conventional method using blue dye and/or radiocolloid (B/R). In almost all cases, contrast‐enhanced lymphatic vessels were clearly visualized by US soon after the periareolar injection of SNZ and the SLNs were easily identified with an identification rate of 98% (98/100) for SNZ and 100% (100/100) for B/R. The number of SLNs identified by SNZ (SNZ‐SLN) (mean per patient, 1.52) was significantly lower than that identified by B/R (B/R‐SLN) (2.19) (P < 0.0001). Twenty‐five patients with positive SLNs had at least one positive SNZ‐SLN. On a node‐by‐node basis, sensitivity, specificity, and accuracy of FNAC for SNZ‐SLNs (n = 149) were 33.3%, 99.2%, and 85.9%, respectively. Identification of SLN by periareolar injection of SNZ is a technically simple method with an identification rate as high as 98%. SNZ‐SLN thus seems to be a good target for FNAC, but sensitivity of FNAC for SNZ‐SLNs needs to be improved.

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