A unique tumor measuring 8 x 8 x 5 mm and composed of adenoma, adenocarcinoma and mixed carcinoid-adenocarcinoma arising in the ascending colon is reported. The mixed carcinoid-adenocarcinoma, in which adenocarcinomatous and carcinoid components intermingled, originated in the mucosa, penetrated the muscularis mucosa and extended into the submucosa. Immunohistochemically, carcinoid cells were positive for neuroendocrine markers and adenocarcinoma cells were intracytoplasmicly positive for carcinoembryonic antigen. Ultrastructurally, membrane-bound electron dense granules varying in shape, size and electron density were detected in the cytoplasm of carcinoid cells. No mutations of p53 and k-ras genes were detected in adenomatous, adenocarcinomatous or mixed carcinoid-adenocarcinoma components. The morphological appearances of the present case strongly suggests the histogenesis of this tumor in an adenoma-adenocarcinoma-carcinoid tumor sequence.

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DNA aneuploidy, p53 overexpression, and high cell proliferation frequently occur in gastric cancer. However, little is known about the time of their appearance throughout cancer progression. Therefore, the objective of the present study was to determine when such abnormalities occur during gastric cancer progression. We classified the gastric cancers examined into intestinal (n = 65) and diffuse (n = 34) types. DNA ploidy was examined using flow cytometry and expression of MIB‐1 and p53 immunoreactivity were studied using the avidin‐biotin complex method in three stages of gastric cancer (mucosal, submucosal, deeply invasive cancer, i.e., advanced cancer). The incidence of DNA aneuploidy in intestinal‐type mucosal cancers (15/27, 55.6%) was lower than that of submucosal invasive cancers (14/16, 87.5%) or advanced cancers (19/22, 86.4%), while a low incidence of DNA aneuploidy was observed in each diffuse‐type cancer group (mucosal, 1/12, 8.3%; submucosal invasive, 3/9, 33.3%; advanced, 8/14, 57.1%). Although overexpression of the p53 gene in intestinal‐type cancer was found in early stage, that in diffuse‐type cancer was observed in advanced stage. Among the intestinal‐type mucosal cancers, the MIB‐1 percent positive was higher in aneuploid tumors than diploid ones. DNA aneuploidy and overexpression of the p53 gene may play an important role in the early tumorigenesis of intestinal‐type gastric cancer and in the late event of tumorigenesis of diffuse‐type gastric cancer. Cytometry (Comm. Clin. Cytometry) 38:111–117, 1999.  © 1999 Wiley‐Liss, Inc.

To evaluate the clinical utility of flow cytometric DNA analysis in gastric cancers, four or more fresh tissue specimens were systematically taken from gastric cancers in 127 consecutive patients including 68 early cancers. DNA ploidy and its variation in individual tumors were determined, and the data were related to clinicopathologic findings. DNA aneuploidy was detected frequently (84.3%) irrespective of tumor progression and correlated significantly with histologic grade (61-2 189.6%1 vs. 6 3 4 176.0%1, P <0.05). DNA ploidy heterogeneity was found in 67.7% of tumors and correlated with invasion depth (mucosa 140.5%1 vs. submucosa-serosa [81.2%1, P <0.001), regional lymph node metastases (negative 158.4%1 vs. positive [82.0%1, P <0.01), and stage grouping (I [58.8%1 vs. Il-IV [86.0%1, P <0.01 1. The maximum DNA index of a tumor correlated significantly with invasion depth (mucosa 11.16, medianl vs. submucosa 11.821, P

A human intestinal spirochete isolated from a rectal biopsy specimen was morphologically characterized. The isolate was comma‐shaped, 3–6 μm in length, 0.2 μm in diameter and had tapered ends. The surface layer, external to the outer envelope, was amorphous. Four string‐like periplasmic flagella with a diameter of 20 nm were presented at each end of the SDS‐treated cells. Thin sections of the bacterial cell revealed a high‐density cytoplasmic membrane and flagella in the periplasmic space between the cytoplasmic membrane and the outer envelope. Three segments of equal length were observed in some of the cells, while other cells were bi‐segmented and more frequently observed.