Immunohistochemical staining of cancer stem cell markers in hepatocellular carcinoma.

BACKGROUND: Cancer stem cells (CSCs) are thought to be a critical subpopulation in tumor development, progression, metastasis and recurrence, and the identification of these cells is an initial step in understanding their role in oncogenesis and in seeking valuable markers for diagnosis or development of targeting therapeutics. AIMS: To identify CSCs in hepatocellular carcinoma (HCC) specimens and define their tissue specificity. METHODS: Immunohistochemical staining of CSC markers: CD44, CD90, CD133 and aldehyde dehydrogenase (ALDH) was performed in 25 HCC specimens, 4 hepatoblastomas, 8 peri-malignant tissues, and 19 cases of viral hepatitis. RESULTS: The positivity of CD44 staining in HCC specimens was significantly lower than in viral hepatitis specimens. The positive rate of CD133 in HCC was similar to viral hepatitis specimens. CD133(+) cells were largely localized to ALDH-positive cells in HCC as revealed by confocal microscopy. In contrast, the co-expression of both markers was visualized within vessels or in the portal areas in viral hepatitis. Moreover, among 7 liver specimens adjacent to HCC tissue, 3-6 samples were positive for CD44, CD90, CD133 and ALDH, especially in dysplastic cells. One of 4 hepatoblastoma cases was positive for all these markers; whereas, the other three specimens were negative for all these CSC markers. CONCLUSIONS: In HCC and dysplastic tissues, clusters of CD133(+)/ALDH(high) cells were identified. The use of cancer stem cell markers to screen tissues with chronic liver diseases provides limited guidance in the identification of malignant cells.

Unusual presentations of eosinophilic gastroenteritis: case series and review of literature.

Eosinophilic gastroenteritis (EG) is an uncommon disease characterized by focal or diffuse eosinophilic infiltration of the gastrointestinal tract, and is usually associated with dyspepsia, diarrhea and peripheral eosinophilia. Diffuse gastrointestinal tract and colonic involvement are uncommon. The endoscopic appearance may vary from normal to mucosal nodularity and ulceration. Gastrointestinal obstruction is unusual and is associated with predominantly muscular disease. We present five unusual cases of EG associated with gastric outlet and duodenal obstruction. Two cases presented with acute pancreatitis and one had a history of pancreatitis. Four cases responded well to medical therapy and one had recurrent gastric outlet obstruction that required surgery. Four out of the five cases had endoscopic and histological evidence of esophagitis and two had colitis. Two patients had ascites. These cases reaffirm that EG is a disorder with protean manifestations and may involve the entire gastrointestinal tract. Gastric outlet and/or small bowel obstruction is an important though uncommon presentation of EG. It may also present as esophagitis, gastritis with polypoid lesions, ulcers or erosions, colitis and pancreatitis and may mimic malignancy.

MYC inactivation uncovers pluripotent differentiation and tumour dormancy in hepatocellular cancer.

Hepatocellular carcinoma is generally refractory to clinical treatment. Here, we report that inactivation of the MYC oncogene is sufficient to induce sustained regression of invasive liver cancers. MYC inactivation resulted en masse in tumour cells differentiating into hepatocytes and biliary cells forming bile duct structures, and this was associated with rapid loss of expression of the tumour marker alpha-fetoprotein, the increase in expression of liver cell markers cytokeratin 8 and carcinoembryonic antigen, and in some cells the liver stem cell marker cytokeratin 19. Using in vivo bioluminescence imaging we found that many of these tumour cells remained dormant as long as MYC remain inactivated; however, MYC reactivation immediately restored their neoplastic features. Using array comparative genomic hybridization we confirmed that these dormant liver cells and the restored tumour retained the identical molecular signature and hence were clonally derived from the tumour cells. Our results show how oncogene inactivation may reverse tumorigenesis in the most clinically difficult cancers. Oncogene inactivation uncovers the pluripotent capacity of tumours to differentiate into normal cellular lineages and tissue structures, while retaining their latent potential to become cancerous, and hence existing in a state of tumour dormancy.

Developmental context determines latency of MYC-induced tumorigenesis.

One of the enigmas in tumor biology is that different types of cancers are prevalent in different age groups. One possible explanation is that the ability of a specific oncogene to cause tumorigenesis in a particular cell type depends on epigenetic parameters such as the developmental context. To address this hypothesis, we have used the tetracycline regulatory system to generate transgenic mice in which the expression of a c-MYC human transgene can be conditionally regulated in murine hepatocytes. MYC's ability to induce tumorigenesis was dependent upon developmental context. In embryonic and neonatal mice, MYC overexpression in the liver induced marked cell proliferation and immediate onset of neoplasia. In contrast, in adult mice MYC overexpression induced cell growth and DNA replication without mitotic cell division, and mice succumbed to neoplasia only after a prolonged latency. In adult hepatocytes, MYC activation failed to induce cell division, which was at least in part mediated through the activation of p53. Surprisingly, apoptosis is not a barrier to MYC inducing tumorigenesis. The ability of oncogenes to induce tumorigenesis may be generally restrained by developmentally specific mechanisms. Adult somatic cells have evolved mechanisms to prevent individual oncogenes from initiating cellular growth, DNA replication, and mitotic cellular division alone, thereby preventing any single genetic event from inducing tumorigenesis.

Correlation of Ki-67, p53, and Adnab-9 immunohistochemical staining and ploidy with clinical and histopathologic features of severely dysplastic colorectal adenomas.

Variations of Ki-67, p53, and Adnab-9 monoclonal antibody reactions in colonic adenomas may be associated with colonic cancer risk. We studied the predictive value of these markers for adverse behavior in severely dysplastic colorectal adenomas, such as an associated carcinoma, multiplicity of adenomas, and subsequent development of adenomas. For this purpose we compared theclinical, gross, and histologic characteristics of highly dysplastic index polyps in 42 patients with Ki 67, p53, and Adnab-9 immunostaining and other molecular markers. Polyps were removed endoscopically, and severely dysplastic polyps were stained immunohistochemically with Ki-67, Adnab-9, and p53 protein by the avidin biotin conjugate (ABC) technique. Quantitative DNA (QDNA) was analyzed by computer-assisted image analysis. Ki-67 immunohistochemistry showed reversal of normal distribution of nuclear staining from the normal basal position to the upper third of the colonic crypts. This abnormality of immunostaining in dysplastic adenomas was the earliest detected by the panel we used. A statistically significant correlation was seen between invasiveness of carcinoma in the index polyp and polyp size (P = 0.003), sessile morphology (P = 0.037), and villous or tubulovillous histology (P = 0.019). In the index adenoma, p53 positivity was correlated with multiplicity at initial examination (P = 0.053), villous histology (P = 0.053), invasiveness of carcinoma (P < 0.003), and recurrence of colorectal adenomas (P = 0.025). Although p53 positivity and aneuploidy were correlated with invasiveness of carcinoma in the index polyp (P = 0.025), Adnab-9 positivity was not. However, Adnab-9 positivity in the index polyp was associated with multiplicity of adenomas (P = 0.04) as well as recurrence of adenomas (P < 0.024). In conclusion, in addition to the morphologic and histologic markers already known, Ki-67, Adnab-9 antibody, and p53 protein may be prognostic indicators useful in follow-up of patients with severely dysplastic colorectal adenomas. Adnab-9 antibody may identify a field defect in above-average-risk adenoma-bearing patients.

Prognostic Significance of the Labeling of Adnab-9 in Pancreatic Intraductal Papillary Mucinous Neoplasms.

First described as a distinct entity in the early1980s (1), pancreatic ductal neoplasms with mucinhypersecretion have been increasingly recognized.This motivated the World Health Organization(WHO) reclassification proposal in 1996 (2), which separated them from mucinous cystic neoplasms.These tumors are now (3) termed intraductal papillarymucinous neoplasms (IPMN). Despite a burgeoningvolume of recent literature devoted to thiscondition, little is known of the pathogenesis ofIPMN,which is believed to constitute 10% of mucinproducingpancreatic tumors and 1% of pancreaticcancers (4). IPMN presents diagnostic and therapeuticchallenges to the clinician because it representsa histologic spectrum of morphology, from thebenign adenoma to invasive carcinoma. The initialhistological and morphological features of IPMN oftenunderestimate its invasive potential (5), and may notaccurately predict survival. Conversely, it may oftenbe difficult to differentiate benign from malignantlesions (5-7). In the most advanced stages, when aninvasive carcinoma is present, IPMN can be indistinguishablefrom common pancreatic ductal cancer(PC), yet with aggressive surgical management, theprognosis for patients with IPMN is far better (6,7).The availability of a prognostic indicator, independentfrom the pathological stage, may help to directtherapy.

AIDS-related myopathy.

Infection with the human immunodeficiency virus (HIV) is often associated with the acquired immunodeficiency syndrome (AIDS), and wasting is one of the defining clinical features of AIDS. Muscular weakness due to myopathy may develop at any stage of HIV infection. We report two illustrative cases of HIV-associated myopathies. One was due to inflammatory myosits most likely directly related to the HIV infection, and the other was most likely the result of mitochondrial damage due to zidovudine, a nucleoside analogue commonly used in treating HIV infection. Biopsies from both patients showed alterations of myofiber structures, of varying severity, culminating in necrosis, lipid droplets, and lymphoplasmocytic inflammatory response. The zidovudine-treated patient also showed distinctive mitochondrial changes, predominantly enlargement, variation in shape and size, and disorganization of the cristae. These two types of HIV-associated inflammatory myopathies are reviewed, along with other HIV-associated myopathies, including HIV wasting syndrome, nemaline rod myopathy, pyomyositis, rhabdomyolysis, cardiomyopathy, and other miscellaneous myopathies associated with HIV infection.