Estudo imunohistoquímico das expressões: hMLH1, hMSH2 e Cox-2 em pólipos do cólon / Study of immunohistochemical expressions of: hMLH1, hMSH2 and Cox-2 in colon polyps

RESUMO

Estudaram-se 167 pólipos, 6 biópsias de mucosa colônica normal e 23 biópsias de adenocarcinomas colorretais coletados por via endoscópica no período de 2000 a 2004 no Hospital Geral da Faculdade de Medicina de Caxias do Sul, quanto à presença de alterações de imunoexpressão do hMLH1, hMSH2 e Cox-2. Houve alteração na imunoexpressão do hMLH1 em por cento, hMSH2 em por cento e Cox-2 em por cento dos adenomas, respectivamente. Não houve associação entre as imunoexpressões e o sexo, idade, localização da lesão, histologia ou displasia. A imunoexpressão para o Cox-2 associou-se ao aumento do número de adenomas no mesmo paciente. As alterações de imunoexpressões de hMLH1 e Cox-2 em adenomas e adenocarcinomas de cólon, em pacientes sem história familial de câncer colorretal, são eventos relativamente freqüentes...

ABSTRACT

The aim of this study was the immunohistochemical expressions hMLH1, hMSH2 and Cox-2 in ressected colon polyps through endoscopy to check alterations in lesions that can be labeled as premature in the carcinogenesis of colorectal cancer. Moreover, the aim was to examine a possible association among the variables: age, sex, localization, size, histology and dysplasia grade. Prospectively, 167 colon polyps were ressected through endoscopies between the years 2000 and 2004 at the Digestive Endoscopy Department of Hospital Geral da Faculdade de Medicina in Caxias do Sul. Six normal colonical mucosa biopsies and 23 biopsies of colorectal adenocarcinomas from different segments were collected. All the material was studied through histopathology and immunohistochemistry. In the tubular adenomas there was loss of expression of the hMLH1 in 37.1 per cent and in 14.5 per cent there was loss of expression of the hMSH2. The Cox-2 was shown to be altered in 7 per cent of the tubular adenomas. There was no loss of expression of the genes hMLH1 e hMSH2 in the villous adenomas; however, the Cox-2 was shown to be altered in 100 per cent of the villous adenomas. In the tubular-villous adenomas there was loss of expression of the hMLH1 in 17.6 per cent and loss of 28.6 per cent of expression of the hMSH2...