During the period of past two years of this particular project, endocrine cell tumors of the gastrointestinal tract were collected and analyzed.
1. Endocrine cell tumors of the gastrointestinal tract were divided into two groups : carcinoid tumor(CD), low-grade malignancy and endocrine cell carcinoma(ECC), high-grade malignancy. Histological differential diagnosis between these two entities was established.
2. CD was thought to be mainly derived from immature endocrine cells. ECC was hypothesized to derive from neoplastic endocrine cell in mucosal tubular adenocarcinoma orade noma, totipotential stem cell, CD, or immature endocrine cell. The first pathway was suspected to be most frequent, followed by the second. These hypothesis was confirmed by molecular level on p53 and LOH.
3. New classification on CD and ECC according to different ocurring sites was established.
4. Difference of p58 protein overexpression and cell proliferation activity between CD and ECC were established. p53 protein overexpression and cell proliferation activity were decreased or lost even in well differentiated ECC cells.
5. Four cell lines established from human esophageal, gastric and rectal ECC revealed a well preservation of hormone(srotonin, peptide YY, calcitonin)-production. Cell line from esophageal ECC was effected by Vincristin and Mitomycin.