RET/PTC oncogene activation is an early event in thyroid carcinogenesis.

RET/PTC oncogene activation occurs in about 20% of human thyroid papillary carcinomas. However, it is not known yet whether it is an early or late event in the process of thyroid carcinogenesis. Here we demonstrate, by using a combined immunohistochemical and reverse transcriptase-polymerase chain reaction based approach, that RET/PTC activation is present in 11 out of 26 occult thyroid papillary carcinomas analysed. Therefore, we conclude that it represents an early event in the process of thyroid cell transformation.

An epidemiologic study of thyroid cancer in Hawaii.

A population-based case-control interview study was designed to test the hypothesis that dietary iodine or the consumption of goitrogenic vegetables increases the risk of thyroid cancer. A total of 191 histologically confirmed cases (64 percent female) and 441 matched controls from five ethnic groups in Hawaii were available for analysis. Among women, intake of seafood (especially shellfish), harm ha (a fermented fish sauce), and dietary iodine were associated with an increased risk of cancer, whereas consumption of goitrogenic (primarily cruciferous) vegetables was associated with a decreased risk. Non-dietary risk factors included miscarriage (especially at first pregnancy), use of fertility drugs, family history of thyroid disease, obesity, and work as a farm laborer. The odds ratio for the combined effect of a high iodine intake and a first-pregnancy miscarriage was 4.8 (95 percent confidence interval [CI] = 1.2-19.2); and for high iodine intake and use of fertility drugs 7.3 (95 percent CI = 1.5-34.5). Among men, positive associations were found for obesity, work as a farm laborer, and a past history of benign thyroid disease. Although this study identified several dietary and non-dietary risk factors for thyroid cancer, it could not fully explain the exceptionally high incidence rates among Filipino women in Hawaii.

Breast cancer in women of Japanese and Caucasian ancestry in Hawaii.

A pathology review of breast cancers in Japanese and Caucasian women indicates more numerous in situ carcinomas in the Japanese. Carcinomas with uniform nuclei were also more numerous among Japanese. Japanese women showed more extensive lymphocytic infiltrates adjacent to their tumors than did Caucasian women, and also showed more conspicuous sinus histiocytosis in tumor-free lymph nodes. Fewer Japanese women had lymph node metastases and those with metastases were less likely to have three or more nodes involved. Of these differences only those relating to local invasion, nuclear grade, lymphocytic infiltration, and sinus histiocytosis were statistically significant, but the demonstrated differences are internally consistent with differences in breast cancer incidence and mortality in the two races. Since the two races share the same medical care system and similar environments, the basis of these differences is probably a genetic modulation of hormonal balance and/or immunologic response.

Histopathological features and their association with steroid receptors in women with breast cancer in Fukuoka, Japan.

In Fukuoka, Japan, infiltrating duct carcinoma predominated among 213 breast cancer cases, age 45 to 74. Lobular and medullary carcinomas were infrequent. About thirty three percent of the women had marked productive fibrosis, based on the UICC code type. Both rough margin and productive fibrosis of the cancer increased with age of the patients. On the contrary, most of accompanying hyperplastic lesions decreased with age. The difference was significant for cystic formation between 10-year age groups of 45-54 and 55-64 (chi 2 = 6.61, p less than 0.02). Hormone receptors of 115 of the cases were independently measured and characterized according to histologic patterns manifesting host reaction (stromal cell infiltration and lymph node histiocytosis). Positive estrogen receptors were more frequent among ductal carcinomas with slight or no cellular reaction than those with extensive cellular reaction. The same pattern was also present for progesterone and androgen receptors. The extent of sinus histiocytosis in lymph nodes without metastasis was also inversely correlated with the presence of these hormone receptors. The correlation was significant for androgen receptor (chi 2 = 5.31, p less than 0.05). Positive estrogen receptor was more common among ductal carcinomas with prominent fibrosis than among those with minimal fibrosis.

Latent thyroid carcinoma in the material of the Institute of Oncology in Gliwice (Poland).

The authors examined microscopically 110 randomly taken thyroid in serial sections. In 10 cases latent papillary thyroid carcinomas were found. The age and sex were without any influence on the incidence. Latent thyroid carcinomas incidence in this material was similar to that reported from the U.S.A., and Canada, but lower than in Japan and among Japanese population of the Hawaian Islands.

Geographic pathology of occult thyroid carcinomas.

Thyroid glands obtained from patients in southeastern Canada, northeastern Japan, southern Poland, western Colombia, and from Japanese living in Hawaii were serially step-sectioned and examined microscopically using identical techniques and diagnostic criteria. The prevalence of occult papillary thyroid carcinoma was significantly higher in Japan (28.4%) and in Hawaiian Japanese (24.2%) when compared with Canada (6%), Poland (9.1%), and Colombia (5.6%). The carcinomas were all papillary except for a single follicular lesion from Colombia. There was no significant sex prevalence. Most of the patients were between 40 and 79 years of age, but there was no particular predominant decade. Only the Colombian series had a large number of younger patients, and they showed a slightly lower prevalence of occult carcinomas before age 40. Most papillary thyroid carcinomas grow slowly and probably remain occult for the life of the patient.