Shozo Ohsumi

Significant Effect of Polymorphisms in CYP2D6 and ABCC2 on Clinical Outcomes of Adjuvant Tamoxifen Therapy for Breast Cancer Patients

PURPOSE The clinical efficacy of tamoxifen is suspected to be influenced by the activity of drug-metabolizing enzymes and transporters involved in the formation, metabolism, and elimination of its active forms. We investigated relationships of polymorphisms in transporter genes and CYP2D6 to clinical outcome of patients receiving tamoxifen. PATIENTS AND METHODS We studied 282 patients with hormone receptor-positive, invasive breast cancer receiving tamoxifen monotherapy, including 67 patients who have been previously reported. We investigated the effects of allelic variants of CYP2D6 and haplotype-tagging single nucleotide polymorphisms (tag-SNPs) of ABCB1, ABCC2, and ABCG2 on recurrence-free survival using the Kaplan-Meier method and Cox regression analysis. Plasma concentrations of tamoxifen metabolites were measured in 98 patients receiving tamoxifen 20 mg/d. RESULTS CYP2D6 variants were significantly associated with shorter recurrence-free survival (P = .000036; hazard ratio [HR] = 9.52; 95% CI, 2.79 to 32.45 in patients with two variant alleles v patients without variant alleles). Among 51 tag-SNPs in transporter genes, a significant association was found at rs3740065 in ABCC2 (P = .00017; HR = 10.64; 95% CI, 1.44 to 78.88 in patients with AA v GG genotypes). The number of risk alleles of CYP2D6 and ABCC2 showed cumulative effects on recurrence-free survival (P = .000000055). Patients carrying four risk alleles had 45.25-fold higher risk compared with patients with <or= one risk allele. CYP2D6 variants were associated with lower plasma levels of endoxifen and 4-hydroxytamoxifen (P = .0000043 and .00052), whereas no significant difference was found among ABCC2 genotype groups. CONCLUSION Our results suggest that polymorphisms in CYP2D6 and ABCC2 are important predictors for the prognosis of patients with breast cancer treated with tamoxifen.

Relation between cancer cellularity and apparent diffusion coefficient values using diffusion-weighted magnetic resonance imaging in breast cancer

PurposeThe purpose of this study was to examine the relation between cancer cellularity and the apparent diffusion coefficient (ADC) value using diffusion-weighted magnetic resonance imaging in breast cancer.Materials and methodsThe subjects were 27 women who had undergone operation for breast cancer. There were 27 breast cancer lesions, 24 of which were invasive ductal carcinoma (IDC) and 3 of which were noninvasive ductal carcinoma (NIDC).ResultsThe mean ADC values of IDC, NIDC, and normal breasts were 1.07 ± 0.19 ·10−3, 1.42 ± 0.17 ·10−3, and 1.96 ± 0.21 ·10−3 mm2/s, respectively. The mean ADC values of IDC and NIDC were signifi cantly different from that of normal breasts (P < 0.001 each). The mean ADC values were also signifi cantly different between IDC and NIDC (P < 0.001). There was no correlation between the ADC value and cancer cellularity.ConclusionThe mean ADC values for breast cancer were significantly different from that of normal breasts. The mean ADC value for breast cancer did not significantly correlate with cancer cellularity but did correlate with histological types.

Feasibility and validity of the Patient Neurotoxicity Questionnaire during taxane chemotherapy in a phase III randomized trial in patients with breast cancer: N-SAS BC 02

GoalsThe aim of the study was to determine the feasibility and validity of a newly developed patient-based instrument—the Patient Neurotoxicity Questionnaire (PNQ)—for grading chemotherapy-induced peripheral neuropathy (CIPN).Patients and methodsWe prospectively collected data from 300 female patients who were treated with taxane chemotherapy for primary breast cancer as part of a national multicenter phase III randomized trial (N-SAS BC 02). We evaluated patient compliance with the PNQ and several validation parameters, including concordance between CIPN grades noted by physicians (National Cancer Institute Common Toxicity Criteria) and patients (PNQ), and the concurrent validity and responsiveness of the PNQ versus the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) utilizing data at pre-treatment and before three, five, and seven treatment cycles.Main resultsThe questionnaire completion rate was >90% at all assessments. Evaluation by physicians always resulted in lower neuropathy assessment scores compared with those reported directly by patients (weighted kappa coefficients, 0.02–0.06). Both PNQ sensory and motor scores were significantly correlated with the FACT/GOG-Ntx (r = 0.66 and 0.51, respectively). In the repeated measures analysis of variance model, PNQ grades increased considerably as treatment continued, indicating progressively worsening CIPN over time.ConclusionsThe PNQ has an applicable degree of feasibility and validity, useful for the diagnosis of CIPN as well as for clinical treatment decision-making, where the development of CIPN is a potential treatment-limiting consideration. Physicians underreport and underestimate the severity of CIPN symptoms compared with patients, thereby supporting the importance of assessing patient-reported outcomes using the PNQ.

Comparison of breast cancer detection by diffusion-weighted magnetic resonance imaging and mammography

PurposeBreast cancer-detecting ability of diffusion-weighted magnetic resonance imaging (DW-MRI) was investigated by comparing the breast cancer detection rates of DW-MRI and mammography (MMG).Materials and methodsThe subjects were 48 women who had breast cancer (53 cancer lesions) who underwent DW-MRI before surgery. Altogether, 41 lesions were invasive ductal carcinoma (IDC), 7 were noninvasive ductal carcinoma (NIDC) and 5 were “others.”ResultsThe breast cancer detection rates by MMG and DW-MRI were 84.9% and 94.3% (P < 0.001), respectively. In each classification of histology and size, the detection rate by DW-MRI was higher than that by MMG. In relation to the mammary gland density, the detection rates of fatty, scattered, heterogeneously dense, and extremely dense mammary glands were 100%, 100%, 92.0%, and 83.3%, respectively. The mean apparent diffusion coefficient values of the histologic types were 1.07 ± 0.17 × 10−3, 1.50 ± 0.24 × 10−3, 1.12 ± 0.25 × 10−3, and 2.01 ± 0.29 × 10−3 mm2/s for IDC, NIDC, others, and normal breast, respectively, showing that the values of IDC and NIDC were significantly different from that of the normal breast (P < 0.001 each). A significant difference was also noted between IDC and NIDC (P < 0.001).ConclusionDW-MRI may be useful for detecting breast cancer in a wide age group of women, including young women with dense mammary glands.

A genome-wide association study identifies locus at 10q22 associated with clinical outcomes of adjuvant tamoxifen therapy for breast cancer patients in Japanese

Although many association studies of polymorphisms in candidate genes with the clinical outcomes of breast cancer patients receiving adjuvant tamoxifen therapy have been reported, genetic factors determining individual response to tamoxifen are not fully understood. To identify genetic polymorphisms associated with clinical outcomes of patients with tamoxifen treatment, we conducted a genome-wide association study (GWAS). We studied 462 Japanese patients with hormone receptor-positive, invasive breast cancer receiving adjuvant tamoxifen therapy. Of them, 240 patients were analyzed by genome-wide genotyping using the Illumina Human610-Quad BeadChips, and two independent sets of 105 and 117 cases were used for replication studies. In the GWAS, we detected significant associations with recurrence-free survival at 15 single-nucleotide polymorphisms (SNPs) on nine chromosomal loci (1p31, 1q41, 5q33, 7p11, 10q22, 12q13, 13q22, 18q12 and 19p13) that satisfied a genome-wide significant threshold (log-rank P= 2.87 × 10(-9)-9.41 × 10(-8)). Among them, rs10509373 in C10orf11 gene on 10q22 was significantly associated with recurrence-free survival in the replication study (log-rank P= 2.02 × 10(-4)) and a combined analysis indicated a strong association of this SNP with recurrence-free survival in breast cancer patients treated with tamoxifen (log-rank P= 1.26 × 10(-10)). Hazard ratio per C allele of rs10509373 was 4.51 [95% confidence interval (CI), 2.72-7.51; P= 6.29 × 10(-9)]. In a combined analysis of rs10509373 genotype with previously identified genetic makers, CYP2D6 and ABCC2, the number of risk alleles of these three genes had cumulative effects on recurrence-free survival among 345 patients receiving tamoxifen monotherapy (log-rank P= 2.28 × 10(-12)). In conclusion, we identified a novel locus associated with recurrence-free survival in Japanese breast cancer patients receiving adjuvant tamoxifen therapy.

Lessons for pharmacogenomics studies: association study between CYP2D6 genotype and tamoxifen response.

We earlier reported a significant association between the cytochrome P450 2D6 (CYP2D6) genotype and the clinical outcome in 282 Japanese breast cancer patients receiving tamoxifen monotherapy. Although many research groups have provided evidence indicating the CYP2D6 genotype as one of the strongest predictors of tamoxifen response, the results still remain controversial. We hypothesized that concomitant treatment was one of the causes of these controversial results. We then studied 167 breast cancer patients who received tamoxifen-combined therapy to evaluate the effects of concomitant treatment on the association analysis and observed no significant association between CYP2D6 genotype and recurrence-free survival (P=0.44, hazard ratio: 0.64, 95% confidential interval: 0.20-1.99 in patients with two variant alleles vs. patients without a variant allele). When we carried out two subgroup analyses for nodal status and tumor size, we observed a positive association between the CYP2D6 genotype and the clinical outcome only in patients who received tamoxifen monotherapy. This study explained a part of the discrepancies among the reported results.

INDUCTION OF UNDIFFERENTIATED TUMORS BY JC VIRUS IN THE CEREBRUM OF RATS

Newborn Sprague‐Dawley rats were inoculated intracranially with JC virus (Tokyo‐1), a human polyomavirus, which had been isolated by Nagashimaet al. from the autopsied brain of a patient with progressive multifocal leukoencephalopathy in Japan. Twenty‐one to 70 weeks later, 21 of 27 rats developed brain tumors in the cerebrum, but not in the cerebellum. Most of the tumor cells were of an undifferentiated neuroectodermal nature and showed nuclear palisades and pseudorosettes. In some tumor cells glial flbrillary acidic protein was positive immunohistochemically, and many glial filaments were demonstrated ultrastructurally. Neuronal differentiation was not proved. Two continuous lines of cultured tumor cells were established, and T antigen of JCV (Tokyo‐1) was present in both cell lines. Glial differentiation was confirmed also in the tumors produced by subcutaneous transplantation of cultured tumor cells.

Feasibility study of docetaxel with cyclophosphamide as adjuvant chemotherapy for Japanese breast cancer patients.

OBJECTIVE The 7-year follow-up of the US oncology 9735 trial demonstrated the superiority of TC [docetaxel (DTX)/cyclophosphamide (CPA)] to doxorubicin/CPA therapy. To introduce TC therapy in Japan, the verification of the safety and tolerability is essential. We performed a collaborative prospective safety study with Okayama University to introduce TC therapy. METHODS The subjects were 53 patients aged from 33 to 67 years at intermediate risk based on the St Gallen risk classification who underwent radical surgery for primary breast cancer between August 2007 and December 2008. As post-operative adjuvant chemotherapy, four cycles of TC (DTX 75 mg/m(2) + CPA 600 mg/m(2)) were administered at 3-week intervals. Adverse events were evaluated based on National Cancer Institute-Common Terminology Criteria for Adverse Events ver. 3.0. The safety and completion rate were evaluated as the primary and secondary endpoints, respectively. RESULTS Regarding hematological toxicity, Grade (G) 4 neutropenia occurred in 71.7% and G3 in 26.4%. G3-4 leukopenia developed in 32.1% and 56.6%, respectively, G4 anemia in 1.9% and G1-2 anemia in 26.4%. Regarding non-hematological toxicity, systemic malaise, skin eruption, edema, myalgia, arthralgia and nausea were noted in most patients. The completion rate was 94.3%, dose reduction was necessary in 7.5% and granulocyte colony-stimulating factor (G-CSF) support was required in 17.0%. On comparison between patients aged 65 years or older and younger than 65 years, the completion rate, dose reduction and incidence of febrile neutropenia (FN) were higher in the elderly patients. G-CSF support was more often needed in this subgroup. CONCLUSIONS TC therapy is tolerable for Japanese patients, but attention should be paid to the development of FN and neutropenia. The completion rate was lower in the elderly patients, showing that tolerability was not necessarily favorable.

Probiotic Beverage with Soy Isoflavone Consumption for Breast Cancer Prevention: A Case-control Study.

The purpose of this study is to evaluate how beverages containing Lactobacillus casei Shirota (BLS) and soy isoflavone consumption since adolescence affected the incidence of breast cancer. In a population-based case-control study, three hundred and six cases with breast cancer and 662 controls aged 40 to 55 were matched for age and residential area and included in the analyses. Diet, lifestyle and other breast cancer risk factors were investigated using the self-administered questionnaire and interview. Odds ratios (ORs) of BLS and soy isoflavone consumption for breast cancer incidence were independently and jointly estimated using a conditional logistic regression. The ORs of BLS consumption (≥ four times a week against < four times a week) was 0.65 and statistically significant (p = 0.048). The analysis of association between soy consumption and breast cancer incidence showed the more the isoflavone consumption is, the lower the odds of breast cancer becomes. Adjusted ORs for breast cancer in the second, the third and the fourth quartiles of soy consumption against the first quartile were 0.76, 0.53 and 0.48, respectively (trend test, p = 0.0002). The BLS-isoflavone interaction was not statistically significant; however, a biological interaction was suggested. Regular consumption of BLS and isoflavones since adolescence was inversely associated with the incidence of breast cancer in Japanese women.

Occult Breast Carcinoma Presenting with Axillary Lymph Node Metastases : Follow-up of Eleven Patients

BackgroundBreast carcinoma presenting with axillary metastases and no clinically apparent primary tumor in the breast is an uncommon form of stage II disease. The methods of diagnosis and treatment of these patients are not established. We present our eleven treated cases of occult carcinoma and discuss the issues of evaluation and management.MethodsEleven patients with occult breast carcinoma (OBC) presenting between January, 1985 and April, 1998 at the National Shikoku Cancer Center were evaluated clinically and with immunohistochemical staining. Immunohistochemical staining was performed using the Envision method. The primary antibodies for gross cystic disease fluid protein-15 (GCDFP-15), estrogen receptor (ER) and progesterone receptor (PR) were used.ResultsNine patients underwent mastectomy. Breast-conserving surgery was performed in one patient. One patient did not receive any operation for the breast. No primary tumor was found among three of nine cases receiving mastectomy. Some adjuvant therapies after the operation were performed in eight cases. Follow-up ranged from 5 to 310 months (median, 54 months), and the five-year disease free survival rate was 62.5%. There were eight GCDFP-15 positive cases (72.7%) and four ER and/or PR positive cases (36.4%).ConclusionsGCDFP-15 is useful for confirming the primary site of breast carcinoma. Ultrasonography, computed tomography, and magnetic resonance imaging are thought to be good for detecting occult primary tumors. The incidence of OBC is still unclear, but it is possible that these patients need to be treated as typical stage II patients.