Immunohistochemistry and c-kit gene analysis in determining malignancy in gastrointestinal stromal tumors.

BACKGROUND/AIMS: Usefulness of immunohistochemistry and c-kit proto-oncogene mutation was examined for determining malignancy in 24 cases of gastrointestinal stromal tumors.

METHODOLOGY

Cases were histologically diagnosed and subjected to immunohistochemical staining and c-kit gene analysis. All parameters were compared to prognosis.

RESULTS

There were significant differences in tumor size, central necrosis, mitotic activity and histological diagnosis between recurrent and non-recurrent cases. Positivity to KIT staining was 100% in recurrent and 87.5% in non-recurrent cases. Positivity to Ki-67 and p53 staining were significantly higher in recurrent cases than in non-recurrent cases. Mutations in exon 11 of the c-kit gene were significantly more frequent in recurrent cases than in non-recurrent cases.

CONCLUSIONS

Histological diagnosis, tumor size, central necrosis, and mitotic activity were reconfirmed to be indicators for recurrence of gastrointestinal stromal tumors. Furthermore, it is suggested that positivity of Ki-67 and p53 immunostaining and c-kit gene mutation also need to be done for prediction of recurrence.