RESUMO
<p><b>OBJECTIVE</b>Hirschsprung's Disease (HD) and allied Hirschsprung's disorder (HAD) have very similar clinical manifestations, but there are many different theories about the two diseases. The present study was designed to understand the expression of Ret protein in HD and HAD, and to explore the role of Ret protein in the pathogenesis of HD and HAD.</p><p><b>METHODS</b>Colon specimens from patients with confirmed HD and HAD, including 15 cases of HD (male 12, female 3) and 11 cases of HAD (male 8, female 3) were collected for this study. At the same time normal colon specimens from 10 individuals with other diseases were used as control. The expression of Ret protein in the intestinal tissue was detected by using immunohistochemical SABC technique with mouse anti-Ret monoclonal antibody.</p><p><b>RESULTS</b>In the colon specimens from normal controls and the dilated segments of colon from HD and HAD patients, moderate to large number of Ret-positive cells were observed among the ganglion cells of myenteric plexuses and submucosal plexuses (P > 0.05). On the contrary, Ret-positive cells were not seen in the stenotic segment of colon from HD patients. But there was positive staining in the stenotic segment of the colon from HAD. Moreover, giant ganglion cells showing strongly positive staining could be seen. There were also displastic cells, small cells, and cells with irregular shape. Statistical analysis showed significant differences in Ret cells positivity between the stenotic segment of colon of HD and the normal control (P < 0.001) as well as between HD and HAD (P < 0.001).</p><p><b>CONCLUSION</b>Ret protein may play an important role in the pathogenesis of HD and could not have definite relationship with HAD.</p>