Common fragile site expression and genetic predisposition to breast cancer

The expression of common fragile sites induced by aphidicolin and caffeine was evaluated on prometaphase obtained from the peripheral blood lymphocytes of 35 women with breast cancer, their 35 clinically healthy female family members, and 20 sex- and age-matched normal controls. As a result of the cytogenetic and statistical evaluation, the number of damaged cells, chromosomal aberrations, and expression frequencies of fragile sites detected in patients with breast cancer and their first-degree relatives were found to be significantly higher than those in the control group. Our findings indicate an increased genetic instability in women with breast carcinomas and their relatives. Therefore, fragile sites may be used as a reliable marker for defining genetic susceptibility to cancer in general.     

Possible consequences of applying guidelines to healthy women with a family history of breast cancer

Possible effects of consistently applying published guidelines on healthy women with breast cancer in their family history were analysed. We investigated 1060 unrelated breast cancer patients and calculated the numbers of first-degree relatives that would be referred to a familial cancer clinic if the guidelines were consistently applied. A first-degree relative was considered a candidate for referral if she was female, without breast cancer at the moment of the interview, alive and over the age of 24. The criteria for referral were based on one Dutch and two British guidelines. According to the Dutch guideline, for one affected woman with breast cancer, 0.25 (95% CI 0.22-0.28) healthy first-degree female relatives should be offered a consultation at a familial cancer clinic (FCC). Application of the British guidelines would lead to a similar number of referrals. Of all healthy first-degree female relatives, who should be referred to an FCC, 34-37% had an index case among their family who was already known at a genetic department. If current guidelines are consistently applied, a sharp increase in referrals to FCCs may be expected. These guidelines, however, are arbitrary and only limited data are available on the efficacy of this surveillance for high-risk healthy women.     

Spontaneous chromosomal instability in breast cancer families

Spontaneous chromosomal instability has been correlated with cancer predisposition. In the present study, the phenomenon has been evaluated using two cytogenetic markers, namely, frequency of spontaneous sister chromatid exchanges (SCE) and spontaneous chromosomal aberrations (CA) in peripheral blood lymphocytes of hereditary breast cancer (HBC) patients (n = 11) and healthy blood relatives (HBR, n = 36). A statistically significant difference was observed for both the endpoints between HBC patients and controls (P < 0.001), HBC patients and HBR (P < 0.001), as well as HBR and controls (P < 0.001). Thus, 63.64% of the HBC patients and 25% of HBR showed a mean CA/cell value higher than the highest mean CA/cell value of the controls (0.11 CA/cell). Similarly, 81.81% of the HBC patients and 61.11% of HBR showed a mean SCE/cell value higher than the highest mean SCE/cell value of the controls (9.60 SCE/cell). Chromosomal aberrations were more frequently observed in the B and E group of chromosomes in HBC patients and HBR. These findings primarily indicate the high level of chromosomal instability in breast cancer families, and might be one of the predisposing factors for high risk of cancer in HBR.     

Sister chromatid exchange analysis in familial groups of malignant melanoma patients

Sister chromatid exchange (SCE) analysis was carried out on peripheral blood lymphocytes of 20 familial malignant melanoma (FMM) and 39 sporadic malignant melanoma (SMM) untreated patients, belonging to 10 and 39 families, respectively. The study was extended to 39 unaffected close relatives of FMM patients, to 187 unaffected close relatives of SMM patients, and to 20 unaffected unrelated individuals (control group), all examined under the same conditions. The mean SCE rates/cell were significantly higher in MM families than in the control group, and in melanoma patients than in their close relatives. The mean SCE levels of FMM and SMM patients, (8.4 +/- 0.8 and 8.0 +/- 0.3, respectively) were similar, and so were the distributions of individuals in classes of increasing SCE values (with a modal value at 7-8 SCEs/cell). The mean SCE levels of close relatives of FMM and SMM patients were also similar (5.4 +/- 0.2 and 5.4 +/- 0.1, respectively, with a modal value at 4-5 SCEs/cell), and slightly higher than in the control group (4.7 +/- 0.2 SCEs/cell). More than 7 SCEs/cell were observed in the majority (41 of 59) of FMM or SMM patients, in a smaller fraction (25 of 227) unaffected relatives, and in none of 20 unrelated unaffected individuals. These observations favor the hypothesis that higher SCE levels may be an expression of constitutional lesions predisposing to this neoplastic disease.     

Ultraviolet-induced chromosomal instability in cultured fibroblasts of heterozygote carriers for xeroderma pigmentosum

Fibroblast cultures of seven patients with xeroderma pigmentosum (XP), 19 healthy sibs or parents of XP patients (XP-heterozygotes), and 24 healthy normal controls were studied for chromosome instability induced by ultraviolet rays (UV). We used a UV source that contained predominantly UV-A and UV-B at an intensity of 500 J/m2 and evaluated the induction of micronuclei (MN) and sister chromatid exchange (SCE). the XP homozygotes had a UV sensitivity that was clearly above that of all heterozygotes and normal controls. Heterozygotes had an increased rate of UV-induced MN (4.76 +/- 1.96 vs. 1.82 +/- 2.05, p less than 0.0001) and increased UV induction of SCE (13.21 +/- 3.49 vs. 9.01 +/- 1.25, p less than 0.001), as compared to normal controls. These data support epidemiologic findings that suggest that XP heterozygotes are particularly cancer prone. In addition, the determination of the UV sensitivity in vitro as described may be used for genetic counseling of asymptomatic relatives of XP patients.     

Sister chromatid exchange in malignant lymphomas

Sister chromatid exchange (SCE) was evaluated in peripheral lymphocytes from 20 untreated patients with malignant lymphomas: 6 with Hodgkin's disease (HD), 14 with non-Hodgkin lymphoma (NHL), and 5 with lymphadenitis. The mean SCE frequency (+/- SE) was: 11.2 +/- 0.6, 11.0 +/- 0.6, and 7.2 +/- 0.3 for HD, NHL, and lymphadenitis patients, respectively, and 8.7 +/- 0.2 for the control group. No differences in SCE score were observed in HD and NHL. These results allowed us to consider both groups (HD and NHL) as a single neoplastic population (mean +/- SE, 11.0 +/- 0.4). No significant differences were found between the lymphadenitis and control groups. On the other hand, significantly higher SCE scores were seen in neoplastic populations than in the control and lymphadenitis groups (p less than 0.001 and p less than 0.01, respectively). When SCE was compared by chromosome number and group between neoplastic patients and controls, a higher SCE frequency was observed in chromosomes #1, #2, #3, and B, C + X, E, F chromosome groups than in controls. SCE levels were significantly higher in lymphoma patients in all chromosome numbers and groups mentioned than in patients with lymphadenitis. It is suggested that the high SCE rate in the malignant lymphoma population is possibly related to an increased chromosomal instability.     

Increased spontaneous and mitomycin C-induced sister chromatid exchanges in patients with cancer of the cervix uteri, with special reference to stage of cancer

The frequencies of spontaneous and mitomycin C (MMC)-induced sister chromatid exchange (SCE) were examined in 35 patients with cancer of the cervix uteri (stage 0, eight cases; stage I, nine cases; stage II, nine cases, and stage III, nine cases) before they had undergone cancer treatment, as well as in seven patients with uterine myoma and 18 healthy women as controls. The frequency of SCE was analyzed in reference to the stage of cancer in the cancer group and in reference to chromosome group in the cancer and normal groups. The frequencies of spontaneous and MMC-induced SCE in the cancer group were 10.0 +/- 1.8 and 20.7 +/- 2.6, respectively, and both were significantly higher than in the myoma (8.1 +/- 0.8 and 17.6 +/- 1.8) and normal (7.6 +/- 0.8 and 17.6 +/- 2.3) groups. Furthermore, the frequency of SCE in the cancer group increased with cancer stage. All chromosome groups contributed equally to the increase in SCE in the cancer group. These results indicate that an increase in the frequency of SCE in patients with cervical cancer is related to the presence of cancer, but is not related to a predisposition to cancer.     

Early metabolic defects in persons at increased risk for non-insulin-dependent diabetes mellitus

To identify early metabolic abnormalities in non-insulin-dependent diabetes mellitus (NIDDM), we measured sensitivity to insulin and insulin secretion in 26 first-degree relatives of patients with NIDDM and compared these subjects both with 14 healthy control subjects with no family history of NIDDM and with 19 patients with NIDDM. The euglycemic insulin-clamp technique, indirect calorimetry, and infusion of [3-3H]glucose were used to assess insulin sensitivity. Total-body glucose metabolism was impaired in the first-degree relatives as compared with the controls (P less than 0.01). The defect in glucose metabolism was almost completely accounted for by a defect in nonoxidative glucose metabolism (primarily the storage of glucose as glycogen). The relatives with normal rates of metabolism (mean +/- SEM, 1.81 +/- 0.27 mg per kilogram of body weight per minute) and impaired rates (1.40 +/- 0.22 mg per kilogram per minute) in oral glucose-tolerance tests had the same degree of impairment in glucose storage as compared with healthy control subjects (3.76 +/- 0.55 mg per kilogram per minute; P less than 0.01 for both comparisons). During hyperglycemic clamping, first-phase insulin secretion was lacking in patients with NIDDM (P less than 0.01) and severely impaired in their relatives with impaired glucose tolerance (P less than 0.05) as compared with control subjects; insulin secretion was normal in the relatives with normal glucose tolerance. We conclude that impaired glucose metabolism is common in the first-degree relatives of patients with NIDDM, despite their normal results on oral glucose-tolerance tests. Both insulin resistance and impaired insulin secretion are necessary for the development of impaired glucose tolerance in these subjects.     

First-degree relatives of breast-cancer patients: cognitive perceptions,coping, and adherence to breast self-examination

The author assessed patterns of breast self-examination (BSE) related to cognitive appraisal, coping, and emotional distress in 80 women with first-degree relatives who were breast-cancer patients and 47 matched controls. Participants with first-degree relatives adhered to BSE better than did women with no family history of breast cancer, and women whose relatives had recurrent or metastatic disease performed more BSE than those whose relatives were currently disease free. Greater adherence to BSE was associated with lower levels of depression, more problem-focused coping, older age, and more education. In the women with first-degree relatives, BSE was also associated with higher perceptions of (a) control over prevention, (b) risk for breast cancer, and (c) higher levels of state anxiety. Perception of control, problem-focused coping, depression, and anxiety predicted 35% of the variance in adherence to BSE. The findings suggest that cognitive appraisal, coping strategies, and levels of emotional distress should be considered in designing programs for enhancing adherence to early detection procedures.     

Rare germline mutations in PALB2 and breast cancer risk: a population-based study

Germline mutations in the PALB2 gene are associated with an increased risk of developing breast cancer but little is known about the frequencies of rare variants in PALB2 and the nature of the variants that influence risk. We selected participants recruited to the Women's Environment, Cancer, and Radiation Epidemiology (WECARE) Study and screened lymphocyte DNA from cases with contralateral breast cancer (n = 559) and matched controls with unilateral breast cancer (n = 565) for PALB2 mutations. Five pathogenic PALB2 mutations were identified among the cases (0.9%) versus none among the controls (P = 0.04). The first-degree female relatives of these five carriers demonstrated significantly higher incidence of breast cancer than relatives of noncarrier cases, indicating that pathogenic PALB2 mutations confer an estimated 5.3-fold increase in risk (95% CI: 1.8-13.2). The frequency of rare (<1% MAF) missense mutations was similar in both groups (23 vs. 21). Our findings confirm in a population-based study setting of women with breast cancer the strong risk associated with truncating mutations in PALB2 that has been reported in family studies. Conversely, there is no evidence from this study that rare PALB2 missense mutations strongly influence breast cancer risk.     

MLH1基因415G/C多态与结肠癌遗传易感性的关联研究

目的 探讨MLH1基因415G/C多态与我国汉族人群结肠癌发生的关系.方法 收集97例散发结肠癌患者,138名正常对照,以及5个结肠癌家系的6例结肠癌患者,19名直系亲属.采用聚合酶链反应-限制性片段长度多态性分析法检测外周血MLH1基因415位点多态性.采用逆转录-聚合酶链反应检测各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达.结果 散发结肠癌患者MLH1基因415位点CC基因型频率明显高于正常对照(P=0.035,OR=5.29,95%CI:1.07～26.04).结肠癌家系中患者和直系亲属的C等位基因的频率明显高于散发患者和正常对照(P=0.003和P=0.006).各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达差异无统计学意义.结论 MLH1基因415G/C多态可能是我国散发结肠癌的遗传易感因素,但不是通过下调MLH1 mRNA表达而致病的.结肠癌家系中C等位基因携带者患结肠癌可能性更大.     

MLH1基因415G/C多态与结肠癌遗传易感性的关联研究

目的 探讨MLH1基因415G/C多态与我国汉族人群结肠癌发生的关系.方法 收集97例散发结肠癌患者,138名正常对照,以及5个结肠癌家系的6例结肠癌患者,19名直系亲属.采用聚合酶链反应-限制性片段长度多态性分析法检测外周血MLH1基因415位点多态性.采用逆转录-聚合酶链反应检测各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达.结果 散发结肠癌患者MLH1基因415位点CC基因型频率明显高于正常对照(P=0.035,OR=5.29,95%CI:1.07～26.04).结肠癌家系中患者和直系亲属的C等位基因的频率明显高于散发患者和正常对照(P=0.003和P=0.006).各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达差异无统计学意义.结论 MLH1基因415G/C多态可能是我国散发结肠癌的遗传易感因素,但不是通过下调MLH1 mRNA表达而致病的.结肠癌家系中C等位基因携带者患结肠癌可能性更大.     

MLH1基因415G/C多态与结肠癌遗传易感性的关联研究

目的 探讨MLH1基因415G/C多态与我国汉族人群结肠癌发生的关系.方法 收集97例散发结肠癌患者,138名正常对照,以及5个结肠癌家系的6例结肠癌患者,19名直系亲属.采用聚合酶链反应-限制性片段长度多态性分析法检测外周血MLH1基因415位点多态性.采用逆转录-聚合酶链反应检测各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达.结果 散发结肠癌患者MLH1基因415位点CC基因型频率明显高于正常对照(P=0.035,OR=5.29,95%CI:1.07～26.04).结肠癌家系中患者和直系亲属的C等位基因的频率明显高于散发患者和正常对照(P=0.003和P=0.006).各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达差异无统计学意义.结论 MLH1基因415G/C多态可能是我国散发结肠癌的遗传易感因素,但不是通过下调MLH1 mRNA表达而致病的.结肠癌家系中C等位基因携带者患结肠癌可能性更大.     

MLH1基因415G/C多态与结肠癌遗传易感性的关联研究

目的 探讨MLH1基因415G/C多态与我国汉族人群结肠癌发生的关系.方法 收集97例散发结肠癌患者,138名正常对照,以及5个结肠癌家系的6例结肠癌患者,19名直系亲属.采用聚合酶链反应-限制性片段长度多态性分析法检测外周血MLH1基因415位点多态性.采用逆转录-聚合酶链反应检测各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达.结果 散发结肠癌患者MLH1基因415位点CC基因型频率明显高于正常对照(P=0.035,OR=5.29,95%CI:1.07～26.04).结肠癌家系中患者和直系亲属的C等位基因的频率明显高于散发患者和正常对照(P=0.003和P=0.006).各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达差异无统计学意义.结论 MLH1基因415G/C多态可能是我国散发结肠癌的遗传易感因素,但不是通过下调MLH1 mRNA表达而致病的.结肠癌家系中C等位基因携带者患结肠癌可能性更大.     

MLH1基因415G/C多态与结肠癌遗传易感性的关联研究

目的 探讨MLH1基因415G/C多态与我国汉族人群结肠癌发生的关系.方法 收集97例散发结肠癌患者,138名正常对照,以及5个结肠癌家系的6例结肠癌患者,19名直系亲属.采用聚合酶链反应-限制性片段长度多态性分析法检测外周血MLH1基因415位点多态性.采用逆转录-聚合酶链反应检测各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达.结果 散发结肠癌患者MLH1基因415位点CC基因型频率明显高于正常对照(P=0.035,OR=5.29,95%CI:1.07～26.04).结肠癌家系中患者和直系亲属的C等位基因的频率明显高于散发患者和正常对照(P=0.003和P=0.006).各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达差异无统计学意义.结论 MLH1基因415G/C多态可能是我国散发结肠癌的遗传易感因素,但不是通过下调MLH1 mRNA表达而致病的.结肠癌家系中C等位基因携带者患结肠癌可能性更大.     

MLH1基因415G/C多态与结肠癌遗传易感性的关联研究

目的 探讨MLH1基因415G/C多态与我国汉族人群结肠癌发生的关系.方法 收集97例散发结肠癌患者,138名正常对照,以及5个结肠癌家系的6例结肠癌患者,19名直系亲属.采用聚合酶链反应-限制性片段长度多态性分析法检测外周血MLH1基因415位点多态性.采用逆转录-聚合酶链反应检测各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达.结果 散发结肠癌患者MLH1基因415位点CC基因型频率明显高于正常对照(P=0.035,OR=5.29,95%CI:1.07～26.04).结肠癌家系中患者和直系亲属的C等位基因的频率明显高于散发患者和正常对照(P=0.003和P=0.006).各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达差异无统计学意义.结论 MLH1基因415G/C多态可能是我国散发结肠癌的遗传易感因素,但不是通过下调MLH1 mRNA表达而致病的.结肠癌家系中C等位基因携带者患结肠癌可能性更大.     

MLH1基因415G/C多态与结肠癌遗传易感性的关联研究

目的 探讨MLH1基因415G/C多态与我国汉族人群结肠癌发生的关系.方法 收集97例散发结肠癌患者,138名正常对照,以及5个结肠癌家系的6例结肠癌患者,19名直系亲属.采用聚合酶链反应-限制性片段长度多态性分析法检测外周血MLH1基因415位点多态性.采用逆转录-聚合酶链反应检测各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达.结果 散发结肠癌患者MLH1基因415位点CC基因型频率明显高于正常对照(P=0.035,OR=5.29,95%CI:1.07～26.04).结肠癌家系中患者和直系亲属的C等位基因的频率明显高于散发患者和正常对照(P=0.003和P=0.006).各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达差异无统计学意义.结论 MLH1基因415G/C多态可能是我国散发结肠癌的遗传易感因素,但不是通过下调MLH1 mRNA表达而致病的.结肠癌家系中C等位基因携带者患结肠癌可能性更大.     

MLH1基因415G/C多态与结肠癌遗传易感性的关联研究

目的 探讨MLH1基因415G/C多态与我国汉族人群结肠癌发生的关系.方法 收集97例散发结肠癌患者,138名正常对照,以及5个结肠癌家系的6例结肠癌患者,19名直系亲属.采用聚合酶链反应-限制性片段长度多态性分析法检测外周血MLH1基因415位点多态性.采用逆转录-聚合酶链反应检测各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达.结果 散发结肠癌患者MLH1基因415位点CC基因型频率明显高于正常对照(P=0.035,OR=5.29,95%CI:1.07～26.04).结肠癌家系中患者和直系亲属的C等位基因的频率明显高于散发患者和正常对照(P=0.003和P=0.006).各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达差异无统计学意义.结论 MLH1基因415G/C多态可能是我国散发结肠癌的遗传易感因素,但不是通过下调MLH1 mRNA表达而致病的.结肠癌家系中C等位基因携带者患结肠癌可能性更大.     

MLH1基因415G/C多态与结肠癌遗传易感性的关联研究

目的 探讨MLH1基因415G/C多态与我国汉族人群结肠癌发生的关系.方法 收集97例散发结肠癌患者,138名正常对照,以及5个结肠癌家系的6例结肠癌患者,19名直系亲属.采用聚合酶链反应-限制性片段长度多态性分析法检测外周血MLH1基因415位点多态性.采用逆转录-聚合酶链反应检测各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达.结果 散发结肠癌患者MLH1基因415位点CC基因型频率明显高于正常对照(P=0.035,OR=5.29,95%CI:1.07～26.04).结肠癌家系中患者和直系亲属的C等位基因的频率明显高于散发患者和正常对照(P=0.003和P=0.006).各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达差异无统计学意义.结论 MLH1基因415G/C多态可能是我国散发结肠癌的遗传易感因素,但不是通过下调MLH1 mRNA表达而致病的.结肠癌家系中C等位基因携带者患结肠癌可能性更大.     

MLH1基因415G/C多态与结肠癌遗传易感性的关联研究

目的 探讨MLH1基因415G/C多态与我国汉族人群结肠癌发生的关系.方法 收集97例散发结肠癌患者,138名正常对照,以及5个结肠癌家系的6例结肠癌患者,19名直系亲属.采用聚合酶链反应-限制性片段长度多态性分析法检测外周血MLH1基因415位点多态性.采用逆转录-聚合酶链反应检测各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达.结果 散发结肠癌患者MLH1基因415位点CC基因型频率明显高于正常对照(P=0.035,OR=5.29,95%CI:1.07～26.04).结肠癌家系中患者和直系亲属的C等位基因的频率明显高于散发患者和正常对照(P=0.003和P=0.006).各基因型结肠癌患者正常结肠黏膜的MLH1 mRNA表达差异无统计学意义.结论 MLH1基因415G/C多态可能是我国散发结肠癌的遗传易感因素,但不是通过下调MLH1 mRNA表达而致病的.结肠癌家系中C等位基因携带者患结肠癌可能性更大.