Stephen L. Ewing

Aberrant expression of MUC5AC and MUC6 gastric mucin genes in colorectal polyps

Altered mucin glycosylation and the de novo appearance of gastric mucin antigens have been described in colonic adenomas. The purpose of our study was to determine if expression of the gastric mucin genes MUC5AC and MUC6 occurs in colorectal adenomas and whether this correlates with histopathologic criteria of malignant potential. Immunohistochemical staining using antibodies against MUC5AC and MUC6 tandem repeat synthetic peptides was performed on specimens of normal colon mucosa (n = 26), hyperplastic polyps (n = 9) and adenomatous polyps (n = 111). Mucin mRNA levels were determined using RNase protection assays using riboprobes corresponding to unique non‐repetitive sequences. MUC5AC and MUC6 staining were rarely detected and of low intensity in normal colon and hyperplastic polyps. The number of immunoreactive polyps and intensity of MUC5AC and MUC6 staining were greatest in larger adenomas of moderate villous histology and dysplasia. MUC5AC and MUC6 staining tended to decrease in highly villous polyps with severe dysplasia. Increased MUC5AC mRNA levels were found in 26/45 of adenomas tested compared with 0/9 normal colon specimens. MUC6 mRNA levels were found in 20/45 of adenomas compared with 1/9 normal colon specimens. MUC5AC and MUC6 mRNA were present more frequently and at higher levels in polyps with intermediate stages of size, villous histology and dysplasia. We conclude that aberrant expression of MUC5AC and MUC6 mucin genes is likely responsible for an expanded repertoire of mucin antigen expression in colorectal neoplasia. Int. J. Cancer 80:210–218, 1999. Published 1999 Wiley‐Liss, Inc.

Spectrum of disease in U.S. veteran patients with hepatitis C

OBJECTIVE:Hepatitis C virus (HCV) infection is more prevalent in U.S. veterans attending Veterans Affairs Medical Centers than in the general population. The purpose of this study was to examine the risk factors, psychiatric and substance abuse conditions, and severity of liver disease in veterans with HCV.METHODS:The medical records and liver biopsies of 206 consecutive patients with HCV attending a multidisciplinary medical/psychiatric chronic hepatitis clinic and who met eligibility criteria for interferon α-2b therapy were reviewed.RESULTS:The mean age was 46.5 ± 6.8 yr and 77% were Vietnam-era veterans. Risk factors included i.v. drug use (64%), blood transfusion (15%), and cocaine use (9%), and were unknown in 12%. The average estimated duration of disease was 24 ± 7.6 yr. A history of alcohol abuse or dependence was identified in 80% of patients. Psychiatric illnesses were present in 60%, the most common being depression and posttraumatic stress disorder. Overall, 89% of patients had documented psychiatric and/or substance abuse diagnoses. Severe fibrosis (stages 3–4) was present in 32% and severe inflammation (grades 2–3) was present in 71% of biopsies. Psychiatric and substance abuse diagnoses did not correlate with severity of liver disease. A total of 145 patients (71%) were prescribed interferon-based treatment. The overall virological sustained response rates were 16% after interferon monotherapy and 28% after interferon/ribavirin therapy. Reasons for not receiving interferon therapy included minimal fibrosis on liver biopsy (37 patients [18%]), worsening medical conditions (nine [4%]), and worsening psychiatric and substance abuse problems (14 [7%]).CONCLUSIONS:Advanced fibrosis is common in this cohort of veteran patients with chronic hepatitis C, and the overwhelming majority of these patients have psychiatric and/or substance abuse diagnoses. Despite these comorbidities, the majority received interferon therapies in the context of a multidisciplinary clinic. These data emphasize the importance of hepatitis C care that includes linkage of medical care and psychiatric services.

Leukocytosis and large cell lung cancer. A frequent association.

In a retrospective study of 105 patients with non‐small cell lung cancer during a 5‐year period, 43 had leukocytosis. In 19 of the 43 patients, no clear cut etiology for the leukocytosis was apparent and it was attributed to the tumor itself. In these 19 patients, absolute neutrophilia was detected in 13, eosinophilia was present in three, and eleven exhibited concomitant thrombocytosis. Tumor‐associated leukocytosis occurred predominantly, and eosinophilia exclusively, in patients with large cell pulmonary neoplasms. These results suggest an unusual myeloproliferative stimulus in this type of cancer. It may result from tumor cell production of hemopoietic growth factors such as granulocyte‐macrophage colony‐stimulating activity; however, additional studies are needed to elucidate the underlying mechanism(s), and to determine whether this is a peculiar characteristic of the cells that comprise large cell undifferentiated carcinoma of the lung.

Increased Aggressiveness of Human Prostate PC‐3 Tumor Cells Expressing Cell Surface Localized Membrane Type‐1 Matrix Metalloproteinase (MT1‐MMP)

Membrane type-1 matrix metalloproteinase (MT1-MMP) is a multidomain transmembrane endopeptidase with a major role in physiological and pathological processes through proteolysis of extracellular matrix and other pericellular proteins. We examined cell surface function of MT1-MMP in PC-3 human prostate tumor cells selected for metastasis in nude mice (PC-3-LN4), or transfected with the full-length wild-type (WT) MT1-MMP or with the mutant form lacking the cytoplasmic tail (Delta C-MT1-MMP). Enhanced cell surface MT1-MMP was determined by fluorescence-activated cell sorting analysis and evidenced mechanistically by increased activation of proMMP-2 and invasion into type-I collagen gels. PC-3 cells overexpressing MT1-MMP grew faster than mock-transfected control cells subcutaneously in nude mice. MT1-MMP localized in caveolae, as judged by immunofluorescence microscopy and sucrose-gradient, detergent-resistant cell fractionation. Delta C-MT1-MMP was strongly associated with caveolae, whereas the WT form was present in both caveolae and noncaveolae fractions. The role of plasma membrane MT1-MMP was supported by localization of MT1-MMP by immunofluorescence microscopy at the cell surface of tumor cells in primary prostate cancers. Increased plasma membrane localization of MT1-MMP, either in caveolae or in other lipid raft structures, is a mechanism to localize this proteinase in contact with extracellular matrix and other pericellular proteins, the cleavage of which can facilitate prostate cancer cell invasion and metastasis.

The production of malignant tumors of the lung and pleura in dogs from intratracheal asbestos instillation and cigarette smoking

Nine dogs were given yearly intratracheal instillations of crocidolite asbestos for periods up to three years. The maximum dose totalled 66 mg/kg. In addition, seven of these dogs smoked nine cigarettes per day, five days per week for six years. A malignant pleural and/or peritoneal mesothelioma developed in six of these dogs, and adenocarcinoma of the lung developed in four, one of which had areas of squamous differentiation. The first animal died of a malignant tumor six years after the onset of exposure, and the last animal died eight years after the onset.

Temporal trends in survival after surgical resection of localized non-small cell lung cancer

To test whether modern preoperative staging modalities and perioperative care improve survival after resection of localized non-small cell lung cancer (NSCLC), we retrospectively reviewed outcomes of 454 patients with NSCLC resected from 1947 through 1969 (designated pre-1970 cases), and 540 patients with cancers resected from 1981 through 1994 (designated post-1980 cases). Mean ages, histological subtypes, surgical stages, and types of surgical procedures differed significantly between the two groups. Compared with pre-1970 cases, post-1980 cases were older, had more adenocarcinoma and less squamous cell carcinoma, and had lesser proportions of advanced stage disease. Postoperative (day 30) mortality was significantly higher for resections of localized (stages 1 and 2) NSCLC prior to 1970. For patients surviving at least 30 days after surgery, subsequent survival after resection of localized NSCLC differed minimally between pre-1970 and post-1980 groups. We conclude that perioperative mortality after resection of localized NSCLC improved, but subsequent postoperative survival for these patients did not significantly improve over the 45-year period studied.