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Background: One characteristic of Lynch syndrome, which is caused by germline mutations in a group of genes encoding mismatch repair proteins, is the early onset of colorectal cancer. Here, we report a rare case of juvenile colon cancer, diagnosed based on the onset of intussusception with high microsatellite instability (MSI) and the absence of BRAF mutations, which was suggestive of Lynch syndrome. Case presentation: A 28-year-oldman presented with right lower abdominal pain for approximately 3 months and defecated blacky stool for several weeks. He visited our hospital because of increasingly intense right lower abdominal pain. Computed tomography revealed a contrast-enhanced tumor and lymph nodes with a crab-claw-like fitted image extending into the ascending colon. Colon endoscopy revealed a large submucosal tumor-like lesion with ulceration. Laparoscopy-assisted ileal resection with level 3 lymph node dissection was performed 3 days after the endoscopic reduction of the intussusception. The histological diagnosis was a poorly differentiated adenocarcinoma. Gene analysis of the resected tumor revealed high MSIand KRAS mutations, and the absence of BRAF mutations. Immunohistochemistry indicated the absence of MLH1 and PMS2 expression in tumors. Genetic analysis of peripheral blood and tumors revealed no pathological mutations in MLH1, MSH2, PMS2, or MSH6. Conclusion A rare case of Lynch-like syndrome was diagnosed with intussusception. MSI-high, wild-type BRAF, and the absence of MLH1 and PMS2 expression suggested Lynch syndrome. The absence of pathological mutations in germline and somatic genes suggests the possibility of MLH1 promoter methylation or MLH1 epimutation in the pathogenesis of this case.

We investigated the safety and efficacy of percutaneous hot water injection therapy (PHoT) in six patients with hepatocellular carcinoma (HCC). PHoT produced the marked effect in five (62.5%) of eight lesions. No serious adverse effects have been encountered. We also compared the usefulness of percutaneous ethanol injection therapy (PEIT) (22 patients, 32 lesions) and PHoT (five patients, seven lesions) in patients with HCC with diameter of 3 cm or less. Patients in the PHoT group received significantly fewer treatments than in the PEIT group (P < 0.01), because the volume injected per treatment was greater. Residual cancer was found in five (15.6%) of 32 lesions after PEIT and in three (42.9%) of seven lesions after PHoT, but the difference was not statistically significant. Pain tended to be less frequent in patients treated with PHoT than in patients treated with PEIT. We could not determine whether PHoT was superior to PEIT, but our findings indicate that PHoT may be a safe and effective for treating HCC.

2.5 oligoadenylate synthetase (2.5AS) activity is induced during interferon (IFN) therapy of patients with chronic hepatitis C. It is assumed that the genotype and quantitative level of hepatitis C virus RNA (HCV-RNA) in serum preceding IFN therapy are closely associated with the response to IFN. However, it is not clear whether these viral factors may affect 2.5AS activity during IFN therapy. We analyzed 2.5AS activity during IFN therapy in patients with different genotypes or levels of serum HCV-RNA. However, there were no statistical differences es in 2.5AS activity among them. In the present study, those viral factors were not associated with the induction of 2.5AS activity during IFN therapy, and it is unlikely that differences in response to IFN among patients with different genotypes or quantitative levels of HCV-RNA depend on the 2.5AS pathway.

The purpose of this report is to describe an immunohistological method for detection of proliferating cell nuclear antigen (PCNA/cyclin) in formaldehyde-fixed and paraffin-embedded liver tissue and to clarify the effects of formaldehyde fixation on antigenicity of PCNA/cyclin. For the immunohistological investigation, 34 cases (11 hepatocellular carcinoma, 8 liver cirrhosis, 15 chronic hepatitis) of human liver biopsy specimens were stained by the avidin-biotin peroxidase complex (ABC) method using a commercially available monoclonal anti-PCNA/cyclin antibody (Mab, 19A2). The PCNA/cyclin-positive nuclei of normal or transformed hepatocytes were detected in 11 cases of hepatocellular carcinoma (100%), 7 cases of liver cirrhosis (87.5%) and 12 cases of chronic hepatitis (80%). Various formaldehyde fixation conditions were examined for the regenerative rat liver by changing formaldehyde concentration, fixation time and time interval from resection to fixation. In conclusion, we have found that PCNA/cyclin-positive cell rate of the liver was stabilized within the first 7 days of the fixation. These results suggested that an immunohistological method with anti-PCNA/cyclin antibody might be useful for the routine cell kinetic analysis of the liver.

The identification of nodular lesions, which used to be difficult to differentiate from well differentiated hepatocellular carcinomas, has become frequent since the advent of ultrasonic-guided liver tumor biopsy techniques. This is because adenomatous hyperplasias, which are regarded as putative precancerous lesions, which needed to be differentiated from malignant lesions, often an a nodular. The histological specimens of 52 tumors, obtained from patients with chronic liver injury, were subjected to immunohistological staining for proliferative cell nuclear antigen (PCNA). Findings obtained by this immunohistological technique were compared with those obtained by histological image analysis. Adenomatous hyperplasias with fatty changes or with a high nuclear cytoplasmic ratio on image analysis were frequently PCNA-positive (P

Using immunohistological methods, we studied the lymphoid follicles in liver biopsy specimens obtained from patients with chronic hepatitis C(CH-C) to determine whether they represented an autoimmune manifestation. In 84 specimens obtained by liver biopsy from 76 patients positive for C-100 antibody, we assessed the presence or absence of lymphoid follicles within the portal areas, and then compared the clinical and immunohistological profiles of the two groups defined on this basis. There were no significant differences in the serological and clinical profiles of the two groups, but the T4:T8 cell ratio within the portal areas differed significantly. A T4:T8 cell ratio > 1.0 was more common in the specimens containing lymphoid follicles. This finding resembled the distribution of T cell subpopulations in the portal areas of patients with autoimmune hepatitis, and suggested that lymphoid follicles may be worth investigating to elucidate the relationship between chronic hepatitis C and autoimmune hepatitis.

This study evaluated whether liver regeneration could take place after massive or submassive necrosis of liver cells in 25 patients with several kinds of hepatic failure by immunohistochemical staining for proliferating cell nuclear antigen (PCNA). PCNA positivity was significantly higher (P less than 0.01) in the patients who survived than in the patients who died. Furthermore, PCNA-positive hepatocytes were recognized diffusely in the lobule of the liver in survivors. There was positive correlation between PCNA positivity and plasma concentration of AFP (alpha-fetoprotein), (r = 0.77, P less than 0.01). These results show that liver regeneration could take place after massive necrosis of liver cells in survivors from acute hepatic failure and that immunohistochemical staining for PCNA is useful for prognostic evaluation.