Anabel Ottino

Occult papillary thyroid carcinoma at autopsy in La Plata, Argentina

Although clinically evident thyroid carcinoma is not a frequent neoplasm (incidence 2.7 per 100,000 persons in La Plata, Argentina), occult carcinomas are present in a high proportion of the population, but there are marked differences along geographical lines. The purpose of the present study is to establish the prevalence of occult papillary thyroid carcinoma (OPC) in La Plata. Thyroid glands obtained from 100 consecutive adult necropsies were examined. The material was fixed in buffered formaldehyde at 4°C, serially sectioned at 2 mm intervals, and routinely processed. Eleven thyroid glands contained OPC, corresponding in three cases to multiple lesions. Eight carcinomas were found in 59 men (13.6%) and three in 41 women (7.3%). The ages ranged from 26 to 78 years. The neoplasms varied in size from microscopic foci to 9 mm in diameter. The prevalence rate of OPC in the present study is lower than that found in Finland, Japan, and the US, and higher than for the rest of the series recorded.

Human Papillomavirus DNA and Oncogene Alterations in Colorectal Tumors

The aim of the present study is to determine the presence and molecular integrity of high-risk HPV types in colorectal adenocarcinomas and to assess whether viral DNA is related to common proto-oncogene alterations, such as k-ras mutations and c-myc gene amplification, in colorectal cancer. Seventy-five colorectal adenocarcinomas were screened for HPV infection using nested-PCR (MY09/11-GP5+/6+). HPV typing was performed by type-specific PCR for HPV 16 and HPV 18 DNA. Unidentified samples were subsequently sequenced to determine the viral genotype. The physical status of HPV was determined by a nested PCR approach for type-specific E2 sequences. C-myc amplification was assessed by co-amplification with β-globin as control locus, and mutation in k-ras codons 12 and 13 by ARMS-PCR. Overall, HPV was detected in thirty-three colorectal specimens (44%). HPV 16 was the prevalent type (16/75), followed by HPV 18 (15/75), HPV 31 (1/75) and HPV 66 (1/75). E2 disruption was detected in 56.3% of HPV 16 and in 40% of HPV 18 positive tumors. C-myc amplification was detected in 29.4% of cases, while k-ras mutations in 30.7%. There was no significant trend for HPV infection in tumors harboring either k-ras or c-myc alterations. This study demonstrates HPV DNA and viral integration in colorectal tumors, suggesting a potential role of this virus in colorectal carcinogenesis. There was no concurrence, however, of k-ras and c-myc activation with viral infection.

Solid cell nests of the thyroid gland. Optic and immunohistochemical study at autopsies.

In order to establish the prevalence of solid cell nests (SCN) in adult thyroids, we studied 100 consecutive glands at necropsy. These were serially sectioned and stained with routine and immunoperoxidase techniques in order to detect calcitonin, carcinoembryonic antigen, thyroglobulin and keratin. SCN may be considered as normal thyroid gland components, and they share with C cells a common origin in the ultimobranchial body.