Studies on Relationship between Expression of ras , p53 , c-erbB2 and p53 and Phenotypic Expression Using Mucin Histochemistry in Human Gastric Carcinomas / 대한암학회지

PURPOSE: Recent studies have shown that the expression of mucin is organ- and cell-type specific and it is increasingly possible that its change could result from oncogene activation.To evaluate histogenesis and prognostic factors for gastric carcinoma, we studied the oncoprotein expression in gastric cancer cells classified by mucin phenotye. MATERIALS AND METHODS: Mucin histochemistry and immunohistochemistry for ras, c-erbB2, and p53 oncoprotein expression were performed in 101 surgically resected gastric carcinoma specimens. PAS-Con A, GOS, and HID-AB staining techniques were employed in identifying mucosubstances, RESULTS: Of the 101 specimens studied, 73(72.3%) revealed as having mixture of various mucin-secreting cancer cells. Overall, ras immunoreactivity was observed in 72(71.3%), c-erbB2 in 7(6.9%), and p53 in 47(46.5%). Of the 73 mucus-secreting carcinomas, the surface mucous cell type were shown in 65 (89.0%), the pyloric gland cell type in 48(65,8%), the sialomucin type in 47(64.4%), and the sulfomucin type in 54(74.0%). There was significant association between mucin secretion and ras expression, but not c-erbB2 and p53 expression. There was no significant association between mucin secreting cell types and Lauren classification. Ras expression was correlated with serosal invasion, lymph node metastasis and poor prognosis. CONCLUSION: The phenotypic expression by mucin histochemistry may be not more important for studying of histogenesis in gastric carcinoma than Lauren classification. Ras expression is a poor prognostic indicator and may be correlated with phenotypic expression of surface mucous cell and intestinal cell type in gastric carcinoma.

Cytologic Heterogeneity of Signet Ring Cell Carcinoma of the Stomach: Histochemical and electron microscopic observations

The cytologic heterogeneity of the tumor cells in gastric signet ring cell carcinoma was studied with 13 surgically early gastric carcinoma specimens by means of histochemical stainings on mucin(periodic acid Schiff-alcian blue at pH 2.5, paradoxical concanavalin A, high iron diamine) and electron microscopy. Of the 13 cases of early gastric cell carcinomas, 6 were mucosal type and 7 were submucosal type. Eleven cases consisted of mixture of gastric and intestinal type signet ring cells and the remaining 2 of the mucosal type were entirely made of gastric type. The colonic goblet cell type was found in 4 of the submucosal type. Within the mucosa the tumor cells showed a layering phenomenon; type A signet ring cells were distributed at the central zone and type B and C at the superficial or deeper zone. Each type of signet ring cell showed variable mucin histochemical stainability of gastric and/or intestinal nature. Above finding strongly suggest that the variable phenotypes of signet ring cells result from a heterogeneity of cytoplasmic mucin as well as different stages of differentiation of signet ring carcinoma cells.

Mucin histochemistry by paradoxical concanavalin A staining in early gastric carcinomas

Phenotypic expression of tumor cells was investigated in 33 early gastric carcinomas by mucin histochemistry using paradoxical concanavalin A staining. This staining method had been developed to differentiate 3 classes of mucins located at various sites of the alimentary tract. Twenty-five (76%) tumors contained mixtures of neutral or acid class II mucin and class III mucin, suggesting the origin of multipotential stem cells. The surface mucous cell expression was more dominant than the pyloric gland or intestinal phenotypes in the well-and poorly differentiated adenocarcinomas. The intestinal properties of the tumor cells were noted not only in the well-differentiated but also in the poorly differentiated or signet ring cell carcinomas, not closely being related to the presence of background intestinal metaplasia. Signet ring cell carcinomas revealed a distinct pattern of mucin histochemistry compared with the other types.