Antibodies to MuMTV proteins in the sera of mammary carcinoma patients' healthy daughters.

The presence of antibodies to MuMTV-related proteins in sera of 31 mammary carcinoma patients' healthy daughters have been tested by indirect immunoperoxidase method (ELISA). Ten of them (32.3 +/- 8.4%) reacted with MuMTV proteins preparations, but not with MuLV, RaLV, SSV, MPMV proteins or preparations of mouse embryonic tissues. The percent of positive sera in this group is almost ten times higher than among women without breast cancer in family history (earlier published data). By immunoblotting method the specificity for five positive sera was determined. Two sera react with p27, one with p27 and to a less extent with gp52, one-only with gp52 and one more serum with both proteins equally. Mothers of the daughters with positive-reacted sera were characterized by premenopausal tumors, detected on early (I, IIa) clinical stage of disease.

Association of breast cancer risk with age at first and subsequent births: a study in the population of the Estonian Republic.

Information on reproductive history was obtained from 362 urban breast cancer patients attending the oncological dispensaries at Tallinn and Tartu, Estonian Republic, and from 694 urban women participating in gynecologic screening programs offered by the same centers. The 2 groups were compared by means of Mantel-Haenszel and logistic regression procedures to estimate age-adjusted odds ratios. Women whose first birth occurred before 20 years of age had a breast cancer risk less than one-third the risk of nulliparous women. Risk increased with increase in age at first birth (AFB) but remained below 1.0 (relative to nulliparae), even in the highest AFB categories. The fertility rate in Estonia during the period of this study was relatively low, which facilitated an evaluation of the effect of births subsequent to the first. After adjustment for AFB, it appeared that in this population subsequent births had a protective effect additional to that conferred by the first birth. Moreover, for women who had only 2 children, the age at the time of birth of the second child was a determinant of that effect. Compared to nulliparous women, the breast cancer odds ratio for uniparous women who had their child before age 25 was 0.62, and the ratio for duoparous women who had both their children under that age was 0.18. Neither lactation nor menarche was a risk factor for breast cancer in this pouplation.

Age at menarche, probability of ovulation and breast cancer risk.

An analysis is undertaken of the frequency of ovulation in 17 groups of women aged 15 to 19 who had been the subjects of other studies. A urine specimen of at least 8 h accumulation had been provided on the 20th or 21st day of a menstrual cycle by 681 women. Analysis is restricted to 431 specimens which had been collected between 11 and 3 days prior to the onset of the subsequent menstrual period. A pregnanediol concentration of less than 1 mg per litre in such a specimen was taken as evidence that the cycle was anovular. The probability of a cycle being anovular was inversely and significantly related to the number of years since menarche, and, with years since menarche held constant, was positively but not significantly associated with age at menarche. This observation indicates that women with early menarche do not have a longer duration of exposure to anovular cycles than do those whose menarche is delayed, and that variation in the duration of exposure to post-menarcheal anovular cycles does not explain the association of breast cancer risk with early age at menarche. The 17 groups of women were classified into four categories according to ethnic origin and breast cancer incidence in the populations from which they derived. Anovular cycles were not more common in the high-risk groups; indeed, the two centers in the lowest risk category had the highest proportion of anovular cycles.

Cancer patterns in the oil shale area of the Estonian S.S.R.

Age-adjusted incidence rates of stomach, lung, and skin cancer among urban (1967-1972) and rural (1963-1972) population of four administrative districts in the Estonian S.S.R. have been presented. In the Kohtla-Järve district (oil shale area) there was an excess of stomach and lung cancer. High rates of stomach cancer in towns and boroughs of oil shale area may be explained by migration. A great proportion of migrants comes from regions, where incidence rates are 1.6-2.5. times higher than among estonians. Elevated levels of stomach cancer incidence in rural areas of Kohtla-Järva district remained unexplainable. In a retrospective cohort study of 2069 workers who had been exposed to oil shale products from 10 to 20 years an excess of skin cancer in females was found.