Abstract P5-13-07: Genetic polymorphism of estrogen metabolizing enzyme CYP17A1 rs743572 impacts on serum testosterone level in Japanese premenopausal women

The incidence of breast cancer in Japanese women has doubled in all age groups over the past two decades. We recently demonstrated that this marked increase is mostly due to an increase in the estrogen receptor (ER)-positive subtype, and we created risk prediction models for ER-positive breast cancer in both pre- and post- menopausal women using genetic factors (single nucleotide polymorphism (SNP)), environmental risk factors, serum hormones and growth factors by logistic regression analysis. Serum level of testosterone, which is the precursor of estradiol in estradiol synthesis, was found to be a risk predictor in both pre- and post- menopausal women. On the other hand, it has been reported that some SNPs, including those of estrogen-related genes such as ESR1 and CYP17A1, are correlated with breast cancer risk by genome-wide association studies. To acquire some insights into this mechanism, we analyzed genetic factors (14 SNPs), serum hormones and growth factors (estradiol, testosterone, prolactin, insulin-like growth factor 1 (IGF1) and IGF binding protein 3 (IGFBP3)) in 913 women with breast cancer and 278 disease-free controls for correlation between them.

Serum testosterone and prolactin levels were significantly higher in ER-positive breast cancer patients than in disease-free controls in both pre- (p<0.0001, p<0.0001) and post- (p<0.0001, p = 0.007) menopausal women, and serum estradiol level was significantly higher in ER-positive breast cancer patients than in disease-free controls only in premenopausal women (p = 0.0005). There were significant differences in serum hormone levels among the women with each SNP genotype (homozygotes of major allele, heterozygotes and homozygotes of minor allele), including testosterone among rs743572 genotype (p = 0.014), estradiol among rs827421 genotype (p = 0.016), IGF-1 among rs6905370 genotype (p = 0.032), and prolactin among rs1042522 genotype (p = 0.035) in premenopausal women, as well as estradiol among rs3803662 genotype (p = 0.027) and IGFBP3 among rs6905370 genotype (p = 0.036) in postmenopausal women. In particular, serum testosterone level was significantly different among the rs743572, which is one of the enzymes that convert testosterone to estradiol, of genotypes (AA: 0.308 +/- 0.180 ng/ml, AG: 0.319 +/- 0.193 ng/ml and GG: 0.380 +/- 0.187 ng/ml, p = 0.014). On the other hand, the rs743572 heterozygotes of CYP17A1 have been reported to have increased breast cancer risk than homozygotes of both the major allele and minor allele in premenopausal women. Further studies are required to clarify this mechanism.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-13-07.

Abstract P4-12-06: A mammographic density prediction model using environmental factors, endogenous hormones and growth factors in Japanese women

The incidence of breast cancer in Japanese women has doubled in all age groups over the past two decades, making it important to evaluate breast cancer risk factors in Japanese women. It is well known that mammographic density is positively associated with breast cancer risk in Western countries, and mammographic density is known to be affected by some environmental factors, serum hormones, and growth factors. We performed stepwise variable selection in a multiple regression model with fifteen independent variables as described below, based on the Akaike information criteria (AIC) to build a mammographic density prediction model using a dataset of 1191 women (913 women with breast cancer and 278 disease-free controls). The variables included were: environmental risk factors (body-mass index (BMI), age at menarche, pregnancy, age at first birth, breastfeeding, family history of breast cancer, age at menopause, use of hormone replacement therapy, alcohol intake and smoking), serum hormones and growth factors (estradiol, testosterone, prolactin, insulin-like growth factor 1 (IGF1) and IGF binding protein 3 (IGFBP3)) and mammographic density. The resulting prediction model is:

Mammographic density = + 0.000476 (IGF1) −0.0605 (testosterone) − 0.0508 (IGFBP3) − 0.00683 (age) − 0.0175 (BMI) + 0.00883 (age at menarche) − 0.0153 (breast feeding), (R2 = 0.336).

In this model, IGF1, testosterone, IGFBP3, age, BMI, age at menarche, and breastfeeding were considered to be important factors. IGF1 and age at menarche were positively associated with mammographic density, while on the other hand testosterone, IGFBP3, age, BMI, and breast feeding were negatively associated with mammographic density. Further studies are required to build a modified model incorporating serial measurements of serum hormones and growth factors to take into account time-dependent changes of serum hormones and growth factors, and to assess its accuracy.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-12-06.

P4-10-11: Genetic and Environmental Predictors, Endogenous Hormones and Growth Factors and Risk of Estrogen Receptor-Positive Breast Cancer in Japanese Women

The incidence of breast cancer in Japanese women has doubled in all age groups over the past two decades. We have recently demonstrated that this marked increase is mostly due to an increase in the estrogen receptor (ER)-positive subtype. It is necessary to establish risk factors capable of predicting the risk of ER-positive breast cancer which will enable the efficient selection of candidates for preventive chemotherapy. We analyzed genetic factors, including 14 single nucleotide polymorphisms (SNPs), environmental risk factors (body-mass index (BMI), age at menarche, pregnancy, age at first birth, breastfeeding, family history of breast cancer, age at menopause, use of hormone replacement therapy, alcohol intake and smoking), serum hormones and growth factors (estradiol, testosterone, prolactin, insulin-like growth factor 1 (IGF1) and IGF binding protein 3 (IGFBP3)) and mammographic density in 913 women with breast cancer and 278 disease-free controls. To identify important risk factors, risk prediction models for ER-positive breast cancer in both pre- and postmenopausal women were created by logistic regression analysis. In premenopausal women, 1 SNP (CYP19A1-rs10046), age, pregnancy, breastfeeding, alcohol intake, serum levels of prolactin, testosterone and IGFBP3 were considered to be risk predictors. In postmenopausal women, 1 SNP (TP53-rs1042522), age, BMI, age at menopause, serum levels of testosterone and IGF1 were identified as risk predictors. Risk factors may differ between women of different menopausal status, and inclusion of common genetic variants and serum hormone measurements as well as environmental factors might improve risk assessment models. Further validation studies will clarify appropriate risk groups for preventive chemotherapy.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-10-11.

Adenofibroma of the endometrium after tamoxifen therapy for breast cancer: MR findings

We report a case of adenofibroma of the endometrium in a 69-year-old woman. This patient was receiving tamoxifen therapy after surgery for breast cancer. Magnetic resonance imaging showed an intracavitary mass containing multiple cystic components. We suggest adenofibroma as a possible diagnosis in cases of uterine masses with multiple cystic components and no clinical evidence of malignancy.

FDG-PET findings in sclerosing hemangioma of the lung: a case report

We report a case of sclerosing hemangioma of the lung that showed an intermediately increased accumulation of 18F-fluorodeoxyglucose (FDG) on positron emission tomography (PET). We suggest that FDG-PET may be useful for considering a lesion as benign or low-grade malignant.

Increase in doxorubicin cytotoxicity by inhibition of P-glycoprotein activity with lomerizine

Acquired resistance to chemotherapy is a major problem during cancer treatment. One mechanism for drug resistance is overexpression of the MDR (multidrug resistance)1 gene encoding the transmembrane efflux pump, P-glycoprotein (P-gp). Calcium channel blockers such as verapamil, nifedipine and nicardipine have been shown to reverse cellular drug resistance by inhibiting P-gp drug efflux. This study evaluated whether a new calcium channel blocker, lomerizine, influenced doxorubicin (Dox) cytotoxicity and P-gp activity in a P-gp-expressing cell line compared to a non-expressing subline. Verapamil, and even more markedly, lomerizine, increased cellular uptake of calcein transported by P-gp in a P-gp-expressing erythroleukemia cell line, K562-Dox. Ten microM of lomerizine reduced the IC50 of doxorubicin in the K562-Dox from 60000 ng/ml to 800 ng/ml, whereas the IC50 of doxorubicin in the K562 subline was only marginally affected by these drugs. Lomerizine showed greater reduction in P-gp efflux than verapamil at an equimolar concentration. These results suggest that lomerizine has the clinical potential to reverse tumor MDR involving the efflux protein P-gp.

Inhibitory effect of human immunodeficiency virus protease inhibitors on multidrug resistance transporter P-glycoproteins

The objective of this study was to determine whether human immunodeficiency virus (HIV) protease inhibitors (saquinavir, ritonavir and nelfinavir) interact with other HIV protease inhibitors and/or HIV reverse transcriptase inhibitors (zidovudine, didanosine, lamivudine, zalcitabine and sanilvudine). We measured transport of nelfinavir, an HIV protease inhibitor which is known as a substrate for the multidrug resistance transporter P-glycoprotein (P-gp), in an epithelial monolayer model and Ki for P-gp of some drugs by a calcein flux assay. Transport in a basal to apical direction was 2-fold greater than apical to basal flux for nelfinavir, Ki for P-gp of a potent P-gp inhibitor cyclosporin A was 1.09 microM and those of ritonavir and nelfinavir were 111 microM and 28.6 microM, whereas all HIV reverse transcriptase inhibitors gave high K1 values. These data show that nelfinavir, which is a substrate for P-gp, inhibits a P-gp function as a drug efflux pump and that HIV reverse transcriptase inhibitors do not inhibit P-gp.

[Study of carrier rate and immunity to group B streptococcus (GBS) in unmarried women]

In order to study the carrier rate and immunity to Group B streptococcus (GBS) of unmarried women, an urinary culture was taken and blood serum was assayed by ELISA for type-specific antibody in female students. Heretofore there have been very few reports about GBS in unmarried women in Japan. The validity of urinary culture as a substitute for vaginal culture was initially studied. The carriage of GBS was evaluated by vaginal, anal and urinary cultures in 90 pregnant women. Carrier detection were 18 carriers (20.0%) by vaginal culture, 22 carriers (24.4%) by anal culture and 18 carriers (20.0%) by urinary culture. Fifteen of the 18 subjects (83.3%) detected as carriers by vaginal culture carried the same strain of GBS in urine. Therefore, an urinary culture appears to perform as well as the vaginal culture as a convenient test for GBS. Nineteen (16.2%) of 117 unmarried women had positive urinary cultures for GBS. Among the 19 with positive cultures for GBS, 3 (15.8%) were type Ia, 3 (15.8%) were type Ib, 8 (42.0%) were type III and 5 (26.4%) were other types. Type II was not detected. From the type-specific antibody assay, the histogram of ODI (optimal density index) frequency of types Ia, Ib and III showed a concentration in a relatively narrow range at low ODI, while that of type II was dispersed over a relatively wide range.

Effects of drugs and metabolic inhibitors on the acute toxicity of T-2 toxin in mice

The antidotal effects of antiinflammatory agents, inhibitors of bioamine syntheses, an opioid antagonist and other pharmacological agents on lethal toxicity, leukocytosis and ear inflammation, were investigated in mice subcutaneously administered or topically exposed to T-2 toxin, a trichothecene mycotoxin of Fusarium species. The acute lethal toxicity of T-2 toxin was reduced by administration of the steroidal anti-inflammatory agents, prednisolone and dexamethasone, and prolongation of survival times was demonstrated with an antihistaminic agent, diphenhydramine, and an opioid antagonist, naloxone. Prednisolone also antagonized leukocytosis and the increment of ear weight caused by T-2 toxin. These findings suggest that the action site(s) of steroidal anti-inflammatory agents is involved in the development of the toxic actions of T-2 toxin, and the implications of the results with bioamines and opioids are also discussed.