Tomonori Tanei

Association of Breast Cancer Stem Cells Identified by Aldehyde Dehydrogenase 1 Expression with Resistance to Sequential Paclitaxel and Epirubicin-Based Chemotherapy for Breast Cancers

Purpose: Breast cancer stem cells have been shown to be associated with resistance to chemotherapy in vitro, but their clinical significance remains to be clarified. The aim of this study was to investigate whether cancer stem cells were clinically significant for resistance to chemotherapy in human breast cancers. Experimental Design: Primary breast cancer patients (n = 108) treated with neoadjuvant chemotherapy consisting of sequential paclitaxel and epirubicin-based chemotherapy were included in the study. Breast cancer stem cells were identified by immunohistochemical staining of CD44/CD24 and aldehyde dehydrogenase 1 (ALDH1) in tumor tissues obtained before and after neoadjuvant chemotherapy. CD44+/CD24− tumor cells or ALDH1-positive tumor cells were considered stem cells. Results: Thirty (27.8%) patients achieved pathologic complete response (pCR). ALDH1-positive tumors were significantly associated with a low pCR rate (9.5% versus 32.2%; P = 0.037), but there was no significant association between CD44+/CD24− tumor cell proportions and pCR rates. Changes in the proportion of CD44+/CD24− or ALDH1-positive tumor cells before and after neoadjuvant chemotherapy were studied in 78 patients who did not achieve pCR. The proportion of ALDH1-positive tumor cells increased significantly (P < 0.001) after neoadjuvant chemotherapy, but that of CD44+/CD24− tumor cells did not. Conclusions: Our findings suggest that breast cancer stem cells identified as ALDH1-positive, but not CD44+/CD24−, play a significant role in resistance to chemotherapy. ALDH1-positive thus seems to be a more significantly predictive marker than CD44+/CD24− for the identification of breast cancer stem cells in terms of resistance to chemotherapy.

Stem cell marker aldehyde dehydrogenase 1-positive breast cancers are characterized by negative estrogen receptor, positive human epidermal growth factor receptor type 2, and high Ki67 expression.

Recently, aldehyde dehydrogenase (ALDH) 1 has been identified as a reliable marker for breast cancer stem cells. The aim of our study was to investigate the clinicopathological characteristics of breast cancers with ALDH1+ cancer stem cells. In addition, the distribution of ALDH1+ tumor cells was compared on a cell‐by‐cell basis with that of estrogen receptor (ER)+, Ki67+, or human epidermal growth factor receptor type 2 (HER2)+ tumor cells by means of double immunohistochemical staining. Immunohistochemical staining of ALDH1 was applied to 203 primary breast cancers, and the results were compared with various clinicopathological characteristics of breast cancers including tumor size, histological grade, lymph node metastases, lymphovascular invasion, ER, progesterone receptor, HER2, Ki67, and topoisomerase 2A as well as prognosis. Immunohistochemical double staining of ALDH1 and ER, Ki67, or HER2 was also carried out to investigate their distribution. Of the 203 breast cancers, 21 (10%) were found to be ALDH1+, and these cancers were significantly more likely to be ER− (P = 0.004), progesterone receptor− (P = 0.025), HER2+ (P = 0.001), Ki67+ (P < 0.001), and topoisomerase 2A+ tumors (P = 0.012). Immunohistochemical double staining studies showed that ALDH1+ tumor cells were more likely to be ER−, Ki67−, and HER2+ tumor cells. Patients with ALDH1 (score 3+) tumors showed a tendency (P = 0.056) toward a worse prognosis than did those with ALDH1− tumors. Breast cancers with ALDH1+ cancer stem cells posses biologically aggressive phenotypes that tend to have a poor prognosis, and ALDH1+ cancer stem cells are characterized by ER−, Ki67−, and HER2+. (Cancer Sci 2009; 100: 1062–1068)

Prognostic significance of Ki67 index after neoadjuvant chemotherapy in breast cancer

PURPOSE Recently, Ki67 index (cell proliferation marker) has been attracting a considerable attention as a prognostic factor in breast cancer but the prognostic significance of Ki67 after neoadjuvant chemotherapy (NAC) has rarely been examined. EXPERIMENTAL DESIGN Primary breast cancer patients (n = 102) treated with NAC (sequential paclitaxel 12 cycles (q1w) and 5-FU/epirubicin/cyclophosphamide 4 cycles (q3w)) were recruited in the study. Ki67, estrogen receptor (ER) and progesterone receptor (PR) and breast cancer resistant protein (BCRP) and P-glycoprotein were determined by immunohistochemistry and HER2 was determined by FISH in tumor tissues obtained before and after NAC, and their association with patient prognosis (relapse-free survival) was examined. RESULTS Of the 102 patients, pCR was achieved in 30 (29.4%). In the 72 non-pCR patients, Ki67 index significantly (P < 0.001) decreased after NAC. Ki67 index after NAC, but not Ki67 index before NAC, was significantly associated with a patient prognosis (P = 0.022). Multivariate analysis has shown that Ki67 index after NAC is a marginally significant (P = 0.05) prognostic factor and that other biomarkers including ER, PR, BCRP, and P-glycoprotein before and after NAC are not significant. CONCLUSIONS Ki67 after NAC, but not before NAC, is prognostic in breast cancer patients, and might be clinically useful in the prognosis prediction of patients who do not achieve pCR after NAC. On the other hand, BCRP and P-glycoprotein before and after NAC are unlikely to be useful as prognostic factors in these patients.

Prediction of pathologic complete response to sequential paclitaxel and 5-fluorouracil/epirubicin/cyclophosphamide therapy using a 70-gene classifier for breast cancers.

Sequential administration of paclitaxel plus combined fluorouracil, epirubicin, and cyclophosphamide (P‐FEC) is 1 of the most common neoadjuvant chemotherapies for patients with primary breast cancer and produces pathologic complete response (pCR) rates of 20% to 30%. However, a predictor of pCR to this chemotherapy has yet to be developed. The authors developed such a predictor by using a proprietary DNA microarray for gene expression analysis of breast tumor tissues.

Mutational analysis of MED12 in fibroadenomas and phyllodes tumors of the breast by means of targeted next-generation sequencing

We aimed to analyze MED12 mutation in fibroadenomas (FAs) and phyllodes tumors (PTs) of the breast, which are closely related and consist of epithelial and stromal components. Targeted deep-sequencing using next-generation sequencing was performed in FAs (n = 58) and PTs (n = 27). The frequency of MED12 mutant tumors was significantly higher (P = 0.016) in PTs (74.1 %) than in FAs. (46.6 %). As for FAs, this frequency was significantly higher (P = 0.001) for intracanalicular type (69.0 %) than for other histological subtypes such as pericanalicular, organoid, and mastopathic types (24.1 %). Laser microdissection study revealed that stromal cells, but not epithelial cells, harbored MED12 mutations in both FAs and PTs. MED12 mutation is implicated in the pathogenesis of both FAs and PTs. The similarly high frequency of MED12 mutation in intracanalicular type FAs suggests that they are most closely related to PTs. It is thus speculated that FAs with MED12 mutation are more likely to progress to PTs.

High genomic grade index associated with poor prognosis for lymph node‐negative and estrogen receptor‐positive breast cancers and with good response to chemotherapy

The aim of the present study was to investigate the prognostic value of the genomic grade index for lymph node‐negative and estrogen receptor (ER)‐positive breast cancers of Japanese women treated with adjuvant hormonal therapy alone, as well as the relation between genomic grade index and pathological complete response (CR) to neoadjuvant chemotherapy.

A Case of Bullous Pemphigoid Exacerbated by Irradiation After Breast Conservative Radiotherapy

We present a case, considered to be a form of the Koebner phenomenon, of bullous pemphigoid that was exacerbated mainly within the irradiated field after breast conservative radiotherapy. In May 2009, a 60-year-old woman was diagnosed with bullous pemphigoid, which was treated with steroid therapy. The following month, she was diagnosed with breast cancer (invasive ductal carcinoma, pT1cN0M0). After breast conservative surgery in December 2009, conservative radiotherapy to the right breast was performed (50 Gy in 25 fractions). Portal skin showed no serious change (up to grade 1 skin erythema) and no bullous neogenesis during conservative radiotherapy. However, 2 months after conservative radiotherapy, new blisters became exacerbated mainly within the irradiated field but also in the area outside the irradiated field. Increasing the dosage of oral steroid and minocycline resulted in relief of bullous pemphigoid, although patchy skin pigmentation remained especially in the irradiated skin.

Correlation of Methylated Circulating Tumor DNA With Response to Neoadjuvant Chemotherapy in Breast Cancer Patients.

Micro‐Abstract Correlation of methylated circulating tumor DNA (met‐ctDNA) with tumor response to neoadjuvant chemotherapy (NAC) was evaluated in breast cancer patients. In patients with positive met‐ctDNA before NAC, met‐ctDNA significantly correlated with tumor response and was found to be a more sensitive marker than carcinoembryonic antigen and cancer‐associated antigen 15‐3. The possibility has also been suggested that met‐ctDNA might be useful in monitoring the postoperative recurrence. Background: Circulating tumor DNA (ctDNA) is known to harbor tumor‐specific genetic or epigenetic alterations. In the present study, the correlation of ctDNA with tumor response to neoadjuvant chemotherapy (NAC) was evaluated in primary breast cancer patients. Patients and Methods: Plasma samples were obtained from 87 primary breast cancer patients (stage II‐III) before and after NAC, as well as 1 year after surgery. Methylated ctDNA (met‐ctDNA) was determined by one‐step methylation‐specific PCR (OS‐MSP) for the promoter region of RASSF1A. Results: The positivity (23.0%, 20/87) of met‐ctDNA before NAC was significantly (P < .05) higher than that of carcinoembryonic antigen (CEA) (8.6%) and cancer‐associated antigen (CA) 15‐3 (7.4%). In the patients with positive met‐ctDNA before NAC, met‐ctDNA significantly decreased after NAC in those with disease that responded to therapy (P = .006), but not in patients whose disease did not respond to therapy. Met‐ctDNA after NAC was found to be significantly (P = .008) correlated to the extent of residual tumor burden. Of the 7 patients who showed an increase in met‐ctDNA at 1 year after surgery, 3 developed recurrence. Conclusion: Met‐ctDNA is a more sensitive marker than CEA and CA15‐3, and it might be useful in monitoring the clinical tumor response to NAC. In addition, the potential use of met‐ctDNA as a tumor marker for monitoring postoperative recurrence has been suggested.

Detection of ESR1 mutations in plasma and tumors from metastatic breast cancer patients using next-generation sequencing

PurposeLiquid biopsy using digital PCR (dPCR) has been widely used for the screening of ESR1 mutations, since they are frequently identified in the hotspot. However, dPCR is limited to the known mutations. Therefore, we aimed to analyze the utility of next-generation sequencing (NGS) to discover novel ESR1 mutations.MethodsWhole exon sequencing of the ESR1 gene using NGS was performed in 16 primary and 47 recurrent tumor samples and 38 plasma samples from hormone receptor-positive metastatic breast cancer patients. Functional analyses were then performed for the novel mutations we detected.ResultsWe identified no mutations in primary tumors and six mutations in five recurrent tumors, including three types of known mutations (Y537C, Y537N, and D538G) and two novel mutations (E279V and G557R). We also identified seven mutations in five plasma samples, including three types of known mutations (S463P, Y537S, and D538G) and one mutation not reported in COSMIC database (L536H). All nine patients with ESR1 mutations were treated with aromatase inhibitors (AIs) prior to sampling, and the mutations were frequently detected in patients who received AI treatments in the metastatic setting. Among the three novel mutations (E279V, L536H, and G557R), L536H, but not E279V and G557R, showed ligand-independent activity. All three mutant proteins showed nuclear localization and had no relation with non-genomic ER pathways.ConclusionsAlthough the molecular mechanisms of the E279V and G557R mutations remain unclear, our data suggest the utility of NGS as a liquid biopsy for metastatic breast cancer patients and the potential to identify novel ESR1 mutations.

70-Gene classifier for differentiation between paclitaxel- and docetaxel-sensitive breast cancers

Association of estrogen receptor (ER), progesterone receptor (PR), HER2, Ki67 and 70-gene classifier (70-GC) with a response to paclitaxel (PAC) (n=79) or docetaxel (DOC) (n=55) was investigated in the neoadjuvant setting for breast cancer patients. Sensitivity of breast tumors to PAC, but not to DOC, was found to be significantly associated with ER negativity (P=0.003), PR negativity (P=0.007), and Ki67 positivity (P=0.007). Breast tumors classified into the responders by 70-GC showed a significantly (P=0.005) higher reduction rate to PAC and interestingly a significantly (P=0.009) lower reduction rate to DOC than those classified into the non-responders by 70-GC, suggesting that 70-GC might be useful for the differentiation of PAC-sensitive and DOC-sensitive breast tumors.