Noriko Ikeda

Quantitative analysis of estrogen receptor‐β mRNA and its variants in human breast cancers

We have carried out a quantitative analysis of ER‐α and ER‐β mRNA expression in normal (n = 11) and breast cancer (n = 112) tissues using a real‐time (Taq‐Man) PCR assay. Expression of ER‐β mRNA variants has also been studied by triple‐primer PCR assay. ER‐α mRNA levels in normal breast tissues were significantly (p < 0.01) lower than those in ER‐positive breast cancers but not significantly different from those in ER‐negative breast cancers. However, ER‐β mRNA levels in normal breast tissues were significantly (p < 0.01) higher than those in ER‐positive and ER‐negative breast cancers. Proportions of ER‐β1 and ER‐β2 mRNA expression among total ER‐β mRNA expression were significantly higher and those of ER‐β5 and ER‐β5` mRNA were significantly lower in normal breast tissues than in ER‐positive and ER‐negative breast cancers. ER‐β mRNA levels and proportions of ER‐β mRNA variants did not show any significant correlation with age, tumor size, lymph node status and histological grade. Our results demonstrate that ER‐α mRNA is up‐regulated and ER‐β mRNA is down‐regulated during carcinogenesis of breast cancers. Changes in proportions of ER‐β mRNA variants are also implicated in this process. Int. J. Cancer 88:733–736, 2000.

Quantitative analysis of estrogen receptor‐α and ‐β messenger RNA expression in breast carcinoma by real‐time polymerase chain reaction

Estrogen action is mediated not only through a classic estrogen receptor (ER) (ER‐α) but also through a second ER (ER‐β) that has a structure and function similar to ER‐α. A correlation between ER‐β mRNA expression with ER and progesterone receptor (PR) protein levels as well as prognostic factors remains to be established in breast carcinoma.

Breast cancer risk associated with polymorphism in CYP19 in Japanese women

Screening of the entire coding and major promoter regions of the CYP19 gene identified two novel polymorphisms at codon 39 (Trp to Arg) and codon 408 (silent) in addition to those reported previously at codon 264 (Arg to Cys) and intron 4 [tetranucleotide (TTTA) simple tandem repeat]. A case‐control study was conducted in order to see whether or not these polymorphisms were associated with breast cancer risk in Japanese women. Homozygous and heterozygous carriers of the variant allele Arg at codon 39 showed a significantly decreased risk of breast cancer (OR=0.39, 95%C.I.=0.17–0.89). On the other hand, homozygous carriers of the allele with 10 or more TTTA repeats at intron 4 showed a trend toward an increase (OR=1.80, 95%C.I.=0.97–3.36) in breast cancer risk. Other polymorphisms were found not to be associated with breast cancer risk. These results suggest that the CYP19 polymorphisms at exon 39 and intron 4 would be useful for selecting Japanese women at a high risk of breast cancer. Int. J. Cancer 89:325–328, 2000.

Frequency of BRCA1 and BRCA2 germline mutations in Japanese breast cancer families.

The purpose of this investigation is to study the frequency of BRCA1 and BRCA2 germline mutations in Japanese breast cancer families. Mutation analysis of BRCA1 and BRCA2 by SSCP was conducted on the 113 breast cancer patients (probands) with at least 1 breast cancer (site‐specific breast cancer families, n = 101) or 1 ovarian cancer (breast/ovarian cancer families, n = 12) patient in their first‐degree relatives. Fifteen deleterious mutations (13.3%), including 8 nonsense and 7 frameshift mutations, were identified in BRCA1, and 21 deleterious mutations (18.6%), including 8 nonsense, 12 frameshift and 1 splice‐site mutations, were identified in BRCA2. In site‐specific breast cancer families, mutation frequency of BRCA1 or BRCA2 was high in families with 3 or more breast cancer patients (36%, 9/25), early onset (40 ≤ years old) breast cancer patients (38%, 19/50) or bilateral breast cancer patients (40%, 6/15). In breast/ovarian cancer families, mutations of BRCA1 (58.3%, n = 7), but not BRCA2 (0%, n = 0), were observed. BRCA1 codon 63 (TTA to TAA) nonsense mutation and BRCA2 frameshift mutation (5802 del AATT) were observed in 4 and 7 independent families, respectively. Haplotype analysis has suggested that carriers of each of these mutations have common ancestors. These results demonstrate that family profiles are important determinants of risk for carrying a BRCA1 or BRCA2 mutation and that cumulative frequency of BRCA1 and BRCA2 mutations in Japanese breast cancer families (31.9%) is within the range observed in Caucasian breast cancer families. Presence of Japanese founder mutations has also been suggested. Int. J. Cancer 91:83–88, 2001.

Genetic polymorphism in CYP17 and breast cancer risk in Japanese women.

A case-control study was conducted to investigate the association of two genetic polymorphisms (1931T/C and 1951G/A) in the promoter region of the CYP17 gene with breast cancer risk in Japanese women. No significant association was observed between CYP17 polymorphism(1951G/A) and breast cancer risk (odds ratio (OR) = 1.71, 95% confidence interval (CI): 0.28-1.84). In contrast, a significant increase in breast cancer risk (OR= 1.82. 95% CI: 1.07-3.12) was observed in CYP17(1931C/C) homozygotes compared with CYP17(1931T/C) heterozygotes and CYP17(1931T/T) homozygotes when women aged > or = 55 years were considered, but such a significant increase was not observed when women aged < or = 54 years were considered (OR = 0.96, 95% CI: 0.56-1.63). These results suggest that CYP17 polymorphism(1931T/C) would be useful in the selection of Japanese women at a high risk for developing breast cancer at the age of > or = 55 years.

Surface antigen expression on bladder tumor cells induced by bacillus Calmette-Guérin (BCG): A role of BCG internalization into tumor cells.

Abstract Background: The antitumor mechanisms of bacillus Calmette‐Guérin (BCG) against bladder cancer is still unclear. We previously reported that BCG was internalized by and survived within murine bladder tumor cells (MBT‐2) for at least 40 days. In the present study, we investigated the effect of BCG on the surface antigen expression of bladder tumor cells and the characteristics of these cells as antigen‐presenting cells in vitro.

Expression of antitumor response role of attachment and viability of bacillus calmette—guérin to bladder cancer cells

Background. Antitumor effects of Bacillus Calmette‐Guérin (BCG) against superficial urinary bladder cancer is known to be strong when BCG is directly infused into the bladder cavity. For expression of that effect, attachment of BCG to tumor cells is reported to be essential as the first step. Our study was conducted to elucidate the significance of attachment of BCG to tumor cells in inducing the antitumor effect.

Influence of adjuvant tamoxifen treatment on bone mineral density and bone turnover markers in postmenopausal breast cancer patients in Japan

The effect of adjuvant tamoxifen treatment on bone mineral density (BMD) and bone turnover markers was studied in postmenopausal breast cancer patients. The relationship of tamoxifens effect with the genetic polymorphisms of estrogen receptor (ER)-alpha and ER-beta gene was also studied. Twenty-one postmenopausal breast cancer patients were given tamoxifen (20 mg/day) as the adjuvant treatment after the surgery. BMD of the lumbar supine (dual emission X-rays absorptiometry) and bone resorption (deoxypyridinoline, aminoterminal telopeptide of type I collagen, and carboxyterminal telopeptide of type I collagen) and formation (propeptide of type I procollagen, osteocalcin, and bone-specific alkaline phosphatase) markers were examined at baseline (before the surgery), 6 and 12 months after the start of tamoxifen treatment. Genetic polymorphisms analyzed were TA dinucleotide repeats polymorphism in the promoter region and PvuII and XbaI restriction fragment length polymorphism for the ER-alpha gene and the CA dinucleotide repeats polymorphism in the intron 5 for the ER-beta gene. Tamoxifen significantly increased BMD of the lumbar spine at both 6 (P<0.01) and 12 months (P<0.01) after the start of tamoxifen as compared with that at baseline. The mean percent increase in BMD was 3.3% at 6 months and 2.7% at 12 months. All bone resorption and formation markers significantly decreased at both 6 and 12 months. Among the four genetic polymorphisms studied, only ER-beta CA repeat polymorphism was found to be significantly associated with BMD at 12 months, i.e. BMD of the 21 CA repeats allele carriers was significantly higher than that of the non-carriers (P=0.025). These results suggest that tamoxifen increases BMD of the lumbar supine by reducing the bone turnover in postmenopausal breast cancer patients, and this bone restoring effect of tamoxifen is more marked in ER-beta 21 CA repeats allele carriers than non-carriers.

Bone marrow micrometastases detected by RT-PCR for mammaglobin can be an alternative prognostic factor of breast cancer.

AbstractPurpose. To evaluate a new prognostic factor of breast cancer, bone marrow micrometastases which was detected by RT-PCR for mammaglobin, a sensitive molecular marker of breast cancer, was examined. Materials and methods. One hundred and eleven samples from stage I–III breast cancer patients were examined. Bone marrow micrometastases and clinicopathological parameters, which were age, tumor size, lymph node metastasis and status of the estrogen receptor, were evaluated for the prognostic factor by statistical analysis. Results. Median follow-up time was 21.1 months. Thirty-three (29.7%) out of 111 samples were RT-PCR positive. Eight cases (24.2%) in this group showed recurrent lesions in the distant organs. Whereas six (7.7%) out of 78 RT-PCR negative patients had distant recurrences. In the premenoposal patients, and in the patients with axillary lymph node metastases, RT-PCR positive cases showed significantly higher distant recurrent rate. Bone marrow micrometastases, axillary nodal status, and estrogen receptor were independent prognostic factors for breast cancer by both univariate and multivariate analysis. Conclusions. Bone marrow micrometastases detected by RT-PCR for mammaglobin can be a useful predictive marker for early distant recurrence of breast cancer.

Detection of Breast Cancer micrometastases in peripheral blood using immunomagnetic separation and immunocytochemistry

BackgroundAlthough there have been many reports on the immunocytochemical detection of bone marrow micrometastases in breast cancer patients, peripheral blood micrometastases (PBM) have rarely been studied by immunocytochemistry (ICC)MethodsPBM in operable and metastatic breast cancer patients were studied using immunomagnetic separation of tumor cells followed by immunocytochemistry (IMS-ICC)ResultsPBM were not detected in any peripheral blood samples from 21 healthy women, six patients with benign disease, or in a 21 patients with primary operable breast cancer, of which there were 7 stage I (n=7), 9 stage II, 2 stage III, and 3 inflammatory tumors. On the other hand, PBM were detected in 8 of 29 patients with metastatic breast cancers (27.6%). The number of tumor cells per patient varied from 2 to 90 cancer cells (median: 8 cells). Positivity of PBM was not significantly associated with the first site of recurrence, number of involved organs, tumor marker status, performance status, or disease-free interval, but it was significantly (p<0.01) associated with progesterone receptor negativityConclusionPBM are very rare in primary operable breast cancer patients but can be observed in a considerable number of metastatic breast cancer patients. The clinical significance of PBM still remains to be established.