Variation of p53 mutational spectra between carcinoma of the upper and lower respiratory tract.

Mutations of the p53 tumor suppressor gene are the most common genetic alterations associated with human cancer. Tumor-associated p53 mutations often show characteristic tissue-specific profiles which may infer environmentally induced mutational mechanisms. The p53 mutational frequency and spectrum were determined for 95 carcinomas of the upper and lower respiratory tract (32 lung and 63 upper respiratory tract). Mutations were identified at a frequency of 30% in upper respiratory tract (URT) tumors and 31% in lung tumors. All 29 identified mutations were single-base substitutions. Comparison of the frequency of specific base substitutions between lung and URT showed a striking difference. Transitions occurred at a frequency of 68% in URT, but only 30% in lung. Mutations involving G:C-->A:T transitions, which are commonly reported in gastric and esophageal tumors, were the most frequently identified alteration in URT (11/19). Mutations involving G:C-->T:A transversions, which were relatively common in lung tumors (3/10) and are representative of tobacco smoke-induced mutations were rare in URT tumors (1/19). Interestingly, G:C-->A:T mutations at CpG sites, which are characteristic of endogenous processes, were observed frequently in URT tumors (9/19) but only rarely in lung tumors (1/10), suggesting that both endogenous and exogenous factors are responsible for the observed differences in mutational spectra between the upper and lower respiratory systems.

Assessment of sensitivity and specificity of immunohistochemical staining of p53 in lung and head and neck cancers.

Thirty-two primary carcinomas of the lung and 17 carcinomas of the head and neck (HN) were systematically analyzed for p53 mutations in the highly conserved regions of the gene (exons 5-8). Frozen sections of the same tumors were stained immunohistochemically to assess the sensitivity and specificity of p53 expression as determined by the presence or absence of the protein. On the basis of histology, the lung tumors studied were divided into adenocarcinomas (AC; n = 15), squamous-cell carcinomas (SCC; n = 12), and large-cell carcinomas (LCC; n = 5). All the HN cancers were SCC. Mutations in the p53 gene were detected by direct sequencing of amplified polymerase chain reaction products in six AC of the lungs (40%), three SCC of the lungs (25%), and one LCC (20%), with an overall mutation frequency of 31%. Nine AC (60%) of the lungs, five SCC (42%), and four LCC (80%) were p53-positive by immunohistochemistry. Among HN cancers, p53 mutations were detected in seven tumors (41%). Nine HN tumors (53%) were positive for p53. Negative staining, despite the presence of p53 mutations, was confined to nonsense mutations with truncated p53 and to single-base mutations not causing any change in the amino acid. Although immunohistochemical staining for mutated p53 is sensitive and simple to perform as a screening method, it is not as specific for evaluation of p53 mutations in lung and HN cancers.

Hepatitis viral markers in patients undergoing primary liver transplants.

The purpose of the study was to determine the prevalence in liver transplant (OLTx) patients of the hepatitis markers (anti-A, anti-B, anti-C, anti-D and HBsAg) and the interrelationships between markers and patients' sexes, ages, dates of transplant, clinicopathological diagnoses, and short-term survivals. Slightly more than half of the patients were male. Anti-A and anti-B were about evenly distributed between male and female. Anti-C, anti-D, and HBsAg were far more common in males. Age and year of transplant showed only a moderate increase in anti-A with increasing age. Anti-A was found in 57% of all patients, anti-B in 18%, anti-C in 17%, and HBsAg in 17%. Anti-D was tested only in patients who were positive for anti-B or HBsAg and occurred in 21 (11%) of 185. The poorest short-term survival occurred in males who showed both anti-A and HBsAg.

Response to hepatitis B vaccination by liver transplant candidates.

Liver transplantation (OLTx) is a procedure offered to individuals with advanced liver disease who are expected to live less than a year. Despite improvement in the care of transplant recipients, these patients are exposed to large volumes of blood and, as a result, are at risk to acquire hepatitis. Currently, the only vaccines available for the prevention of hepatitis are those that induce a response to HBsAg. In this study, 144 patients awaiting OLTx and 15 controls were vaccinated three times, once a month, intramuscularly in the deltoid using the Merck Hepatovax plasma-derived vaccine. This schedule was continued regardless of whether or not OLTx occurred before the series was completed. For the 15 controls, the response rate was 93% and for individuals with end-stage liver disease, it ranged from 44 to 54% (P less than 0.004). No difference in the percentage of those developing antibody was detected between groups based upon disease indication or whether the vaccination series was completed before or after OLTx. Of the following: WBC, lymphocytes (percent and number), CD3+ cells (percent and number), CD4+ cells (percent and number), CD8+ cells (percent and number), CD4+/CD8+ ratio, and B cells (percent and number), only the absolute WBC (P less than 0.05) distinguished between those who did and did not develop antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of hepatitis C virus antibody in a liver transplantation population.

The development of a serologic assay to detect antibodies directed at an antigen (C-100-3) of the hepatitis C virus (anti-HCV) has been a major breakthrough in the long search for causative agents of non-A, non-B (NANB) hepatitis. The frequency of HCV in those who have end-stage liver disease is not known. Moreover, the rate of recurrence after liver transplantation (OLTx) and the rate of acquisition of new HCV infection as a result of the OLTx experience is as yet unknown. This study was performed in an attempt to answer these questions. The prevalence of HCV in 372 patients undergoing OLTx at the University of Pittsburgh was determined. Those transplanted for HBV-related liver disease with hepatoma had the highest rate of HCV antibody positivity (45.4%) followed by those with metabolic liver disease (42.5%), putative NANB liver disease (41.4%), and cryptogenic cirrhosis (20.9%); those with cholestatic liver disease exhibited the lowest rate (16.2%). HCV antibody was positive in only 26.3% of patients with hepatoma. Of those patients who were negative prior to transplantation, 12.2% acquired HCV antibody post-OLTx. In the putative NANB group, no difference was detected in the AST and ALT prior to transplantation in either the HCV antibody-positive or -negative patients. In patients with cryptogenic cirrhosis, those who were positive for HCV antibody had higher transaminase levels prior to transplantation than did those patients who were HCV antibody negative.