Takashi Morimoto

Juntendo University, Edo, Tōkyō, Japan

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Publications (5)11.65 Total impact

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    ABSTRACT: Background: Gastric adenocarcinoma with enteroblastic differentiation (GAED) has been recognized as a variant of alpha-fetoprotein (AFP)-producing gastric carcinoma, although its clinicopathologic and immunohistochemical features have not been fully elucidated. Methods: To elucidate the clinicopathologic and immunohistochemical features of GAED, we analyzed 29 cases of GAED, including ten early and 19 advanced lesions, and compared these cases with 100 cases of conventional gastric adenocarcinoma (CGA). Immunohistochemistry for AFP, glypican 3, SALL4, and p53 was performed, and the phenotypic expression of the tumors was evaluated by immunostaining with antibodies against MUC5AC, MUC6, MUC2, CD10, and caudal-type homeobox 2 (CDX2). Results: Lymphatic and venous invasion was more frequent in GAED (76 and 72 %) than in CGA (41 and 31 %; P B 0.001). Lymph node metastasis was more frequently observed in GAED (69 %) than in CGA (38 %; P = 0.005), as were synchronous or metachronous liver metastases (GAED, 31 %; CGA, 6 %; P B 0.001). Immunohistochemically, all GAED were positive for at least one of three enteroblastic linage markers (AFP, glypican 3, and SALL4). Glypican 3 was the most sensitive marker (83 %) for GAED, followed by SALL4 (72 %) and AFP (45 %), whereas no CGA was positive. Furthermore, the rate of positive p53 staining was 59 % in GAED. Regarding the mucin phenotype, CD10 and CDX2 were diffusely or focally expressed in all GAED cases. Invasive areas with hepatoid or enteroblastic differentiation were negative for CD10 and CDX2. Conclusions: Clinicopathologic features of GAED differ from those of CGA. GAED shows aggressive biological behavior, and is characteristically immunoreactive to AFP, glypican 3, or SALL4.
    Full-text · Article · Apr 2015 · Gastric Cancer
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    ABSTRACT: The serrated colorectal carcinoma (CRC) as proposed to arise from serrated adenoma (SA) is characterized by up-regulation of HIF1α, suppression of PTCH or EphB2, loss of DNA repair proteins and BRAF mutation. The aim of this study was to evaluate alterations of these candidates involved in the serrated pathway in colorectal polyps. We analyzed immunoreactivity of these proteins, methylation of PTCH and EphB2, and mutation of BRAF and Kras in sessile SAs (SSAs; n = 32), traditional SAs (TSAs; n = 28), hyperplastic polyps (HPs; n = 24) and conventional adenomas (ADs; n = 21). Increase of nuclear HIF1α expression was more frequent in SA than HP, but less frequent in SA than AD (P < 0.001). Increase of PTCH expression was not found in SSA or HP, but was evident in about half of TSA and all AD (P < 0.001). Decrease of EphB2 expression was more prominent in SA than HP or AD (P ≤ 0.005). Loss of hMLH1 and MGMT expression were most frequent in SSA (P < 0.001). Loss of hMSH2 showed more pronounced in SA and HP than AD (P ≤ 0.004). Methylations of PTCH and EphB2 were rare in all categories. BRAF mutation harbored frequently in SA, but not AD; only AD harbored Kras mutation. This work provides evidence of similarity of HIF1α, EphB2 or DNA repair proteins expression and BRAF mutation in serrated CRCs and their precursors, especially SSA, compared to AD and HP.
    Full-text · Article · Feb 2014 · Journal of Gastroenterology and Hepatology
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    ABSTRACT: Gastric hamartomatous inverted polyp is rare and also difficult to diagnose by forceps biopsy due to its submucosal location. We present three cases of gastric hamartomatous inverted polyps which had similar features and were diagnosed by endoscopy. All three cases were pedunculated lesions. One of the lesions had a size of 35mm─which was too large for the endoscopic snare─so was clipped at the base and resected at the peripheral side of the clip with a needle knife. Lesions in the other two cases were 8mm and 15 mm in size, and were resectable by snare. The surfaces of these lesions appeared to be normal mucosa with some slight depressions. Microscopic findings of the resected specimens showed inverted growth of mucosa and muscularis mucosa into the submucosal layer. These pathological features were compatible with the depressions that had been observed by endoscopy, caused by inverted growth into the submucosal layer.
    No preview · Article · Jan 2013
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    ABSTRACT: To clarify differences in mucin phenotype, proliferative activity and oncogenetic alteration among subtypes of colorectal laterally spreading tumor (LST). LSTs, defined as superficial elevated lesions greater than 10 mm in diameter with a low vertical axis, were macroscopically classified into two subtypes: (1) a granular type (Gr-LST) composed of superficially spreading aggregates of nodules forming a flat-based lesion with a granulonodular and uneven surface; and (2) a non-granular type (NGr-LST) with a flat smooth surface and an absence of granulonodular formation. A total of 69 LSTs, comprising 36 Gr-LSTs and 33 NGr-LSTs, were immunohistochemically stained with MUC2, MUC5AC, MUC6, CD10 (markers of gastrointestinal cell lineage), p53, β-catenin and Ki-67 antibodies, and examined for alteration in exon 1 of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) and exon 15 of v-raf murine sarcoma viral oncogene homologue B1 (BRAF) by polymerase chain reaction followed by direct sequencing. Histologically, 15 Gr-LST samples were adenomas with low-grade dysplasia (LGD), 12 were high-grade dysplasia (HGD) and 9 were adenocarcinomas invading the submucosa (INV), while 12 NGr-LSTs demonstrated LGD, 14 HGD and 7 INV. In the proximal colon, MUC5AC expression was significantly higher in the Gr-type than the NGr-type. MUC6 was expressed only in NGr-LST. MUC2 or CD10 did not differ. P53 expression demonstrated a significant stepwise increment in progression through LGD-HGD-INV with both types of LST. Nuclear β-catenin expression was significantly higher in the NGr-type. Ki-67 expression was significantly higher in the Gr-type in the lower one third zone of the tumor. In proximal, but not distal colon tumors, the incidence of KRAS provided mutation was significantly higher in the Gr-type harboring a specific mutational pattern (G12V). BRAF mutations (V600E) were detected only in two Gr-LSTs. The two subtypes of LST, especially in the proximal colon, have differing phenotypes of gastrointestinal cell lineage, proliferation and activation of Wnt/β-catenin or RAS/RAF/extracellular signal-regulated kinase signaling.
    Full-text · Article · Oct 2012 · World Journal of Gastroenterology

  • No preview · Article · May 2012 · Digestive Endoscopy