Ki67 and p53 in gastrointestinal stromal tumors--GIST.

CONTEXT: Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor. Cellular proliferation and apoptosis is gaining importance for predicting prognosis in several cancers. OBJECTIVE: To investigate the Ki67 and p53 immunostaining in GISTs. METHODS: Specimens from 40 patients with GIST were assessed for immunohistochemical expression of Ki67 and p53. The tumors were divided according the risk of recurrence in two groups: I with high or intermediate risk and; II with low or very low risk. RESULTS: Among the 40 patients, 21 were men, the mean age was 56 years, 16 occurred in the small intestine and 13 in the stomach, 5 in the retroperitonium, 4 in the colon or rectum and 2 in the mesenterium. Thirty two tumors were from group I and 8 from group II. Half of the patients developed recurrence, being 90% of the group I (P = 0.114). The tumor Ki67 labelling index ranged from 0.02 to 0.35 (mean level 0.12). This index was marginally higher in the group I patients with recurrence (P = 0.09) compared to the patients of the same group without recurrence. p53 staining was expressed in 65% of the GISTs. A higher frequency of p53 and Ki67 had been found in the group I tumors when compared to the other group (P = 0.022; OR = 8.00 - IC 95%: 1.32-48.65). CONCLUSION: The most common site was the small intestine and 80% had a malignant potential justifying the high recurrence observed. No significant correlation was found between p53 and overall outcome of the patients. In group I patients, the evaluation Ki67LI may be a marker of prognosis. The positivity of both markers is higher among the patients with worst prognosis than in the others.

Ki67 and p53 in gastrointestinal stromal tumors - GIST / Ki67 and p53 em tumores estromais gastrointestinais - GIST

CONTEXT: Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor. Cellular proliferation and apoptosis is gaining importance for predicting prognosis in several cancers. OBJECTIVE: To investigate the Ki67 and p53 immunostaining in GISTs. METHODS: Specimens from 40 patients with GIST were assessed for immunohistochemical expression of Ki67 and p53. The tumors were divided according the risk of recurrence in two groups: I with high or intermediate risk and; II with low or very low risk. RESULTS: Among the 40 patients, 21 were men, the mean age was 56 years, 16 occurred in the small intestine and 13 in the stomach, 5 in the retroperitonium, 4 in the colon or rectum and 2 in the mesenterium. Thirty two tumors were from group I and 8 from group II. Half of the patients developed recurrence, being 90 percent of the group I (P = 0.114). The tumor Ki67 labelling index ranged from 0.02 to 0.35 (mean level 0.12). This index was marginally higher in the group I patients with recurrence (P = 0.09) compared to the patients of the same group without recurrence. p53 staining was expressed in 65 percent of the GISTs. A higher frequency of p53 and Ki67 had been found in the group I tumors when compared to the other group (P = 0.022; OR = 8.00 - IC 95 percent: 1.32-48.65). CONCLUSION: The most common site was the small intestine and 80 percent had a malignant potential justifying the high recurrence observed. No significant correlation was found between p53 and overall outcome of the patients. In group I patients, the evaluation Ki67LI may be a marker of prognosis. The positivity of both markers is higher among the patients with worst prognosis than in the others.

CONTEXTO: Os tumores estromais gastrointestinais (GIST) são os tumores mesenquimais mais frequentes. A proliferação intestinal e a apoptose são cada vez mais importantes na avaliação do prognóstico de diversos cânceres. OBJETIVO: Avaliar a imunoexpressão de Ki67 e p53 em GIST. MÉTODOS: Foram estudados a expressão de Ki67 e p53 por imunoistoquimica em tumores de 40 pacientes com GIST. Os tumores foram divididos segundo o risco de recurrência em 2 grupos: I com risco alto ou intermediário e II com risco baixo ou muito baixo. RESULTADOS: Entre os 40 pacientes, 21 eram do sexo masculino, a idade média foi de 56 anos, 16 ocorreram no intestino delgado, 13 no estômago, 5 no retroperitônio, 4 no cólon e reto, e 2 no mesentério. Trinta e dois tumores foram classificados no grupo I e 8 no grupo II. Metade dos pacientes desenvolveu recurrência, sendo 90 por cento de cólon (P = 0,114). O índice de proliferação tumoral Ki67 variou entre 0,02 e 0,35 (média = 0,12). Este índice foi marginalmente superior nos tumores do grupo I com recurrência (P = 0,09), quando comparado aos do mesmo grupo sem recurrência. A expressão do p53 foi observada em 65 por cento dos GISTs. Nos tumores do grupo I foi observada com maior frequência, expressão de p53 e Ki67 (P = 0,022; OR = 8.00 - IC 95 por cento: 1,32-48,65). CONCLUSÃO: A localização mais comum foi no intestino delgado, 80 por cento tinham potencial maligno, justificando a alta recurrência encontrada. Não se observou correlação significante entre p53 e evolução dos pacientes. Nos pacientes do grupo I, a avaliação do KI67LI pode ser um marcador de prognóstico. A positividade dos dois marcadores é maior entre os pacientes de pior prognóstico.