Human papilloma virus (HPV) is possibly involved in laryngeal but not in lung carcinogenesis

Data on human papilloma virus (HPV) involvement in preneoplastic and neoplastic lesions of the larynx and lung are limited and conflicting. The presence of HPV was investigated in a series of laryngeal specimens and non-small cell lung carcinomas (NSCLCs). The laryngeal samples (154) comprised 14 cases with hyperplasia without dysplasia, 49 with dysplasia, and 91 squamous cell carcinomas (SqCCs). The NSCLCs included 31 SqCCs, 32 adenocarcinomas, and 5 undifferentiated large cell carcinomas. Furthermore, we examined, for HPV DNA sequences, 14 bronchial metaplastic squamous lesions located next to cancerous areas. We used a sensitive nested polymerase chain reaction assay (NPCR), dot blotting, and in situ hybridization. The findings were correlated with clinicopathologic features of the patients. In the laryngeal specimens, NPCR analysis showed HPV DNA in 20 (13%) of the 154 specimens. Notably, 19 of 20 HPV-positive cases were carcinomas and only one was a mild dysplastic lesion. Typing of the carcinomas showed single HPV 6, 16, 18, and 33 infection in 1 (1.1%), 12 (13.2%), 2 (2.2%), and 1 (1.1%) samples, respectively, and HPV 6/33, 16/33, and 6/18 coinfection in three carcinomas. In situ hybridization findings were in agreement with PCR results, with the exception of two cases in which HPV 18 DNA was detected only by PCR. HPV was more frequently observed in heavy smokers than in patients with low daily cigarette consumption and nonsmokers (P = .03). There was no correlation between virus infection and gender grade, and lymph node status of the carcinomas. None of the NSCLCs or adjacent metaplastic squamous epithelium contained HPV DNA sequences. The presented data suggest a contributory role of HPV in late stages of laryngeal carcinogenesis, because all premalignant lesions were negative but one. This study does not support a potential role of HPV in the development of NSCLCs. HUM PATHOL 30:274-283. Copyright (C) 1999 by W.B. Saunders Company.</p

Sensitive differential detection of genetically related mycobacterial pathogens in archival material

A polymerase chain reaction (PCR) assay targeted to the immunogenic protein MPB64 gene was used to detect members of the Mycobacterium tuberculosis complex, and an outward-primed PCR (OPPCR) designed on the IS6110 element allowed differentiation between Mycobacterium bovis and Mycobacterium tuberculosis. Additionally, the amplification of IS1110 and 16S ribosomal RNA sequences combined with a dot blotting assay were able to differentially detect Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium paratuberculosis. The validity of the experimental procedure was tested on reference material and formalin-fixed paraffin-embedded samples from patients with tuberculosis, sarcoidosis, or Crohn disease. We demonstrated mycobacterial DNA in 59 of 75 cases,with histologic lesions typical of tuberculosis; we detected M tuberculosis and M paratuberculosis in 6 of 25 sarcoidosis cases and in 7 of 20 Crohn disease specimens, respectively. The proposed diagnostic procedure is directly applicable to archival material and allows differentiation of genetically related mycobacterial pathogens in more detail than other molecular methods. It provides a tool for the diagnostic study, of tuberculosis, sarcoidosis, and Crohn disease

Effects of p53 mutants derived from lung carcinomas on the p53-responsive element (p53RE) of the MDM2 gene

The present study represents a continuation of previous works in which we observed that lung carcinomas co-expressing MDM2 protein and p53 mutants (mt p53) exhibited more aggressive behaviour. In the above studies, we suggested a ‘gain of function’ mechanism of mt p53 proteins based on the fact that the MDM2 gene possesses a p53-responsive element (MDM2-p53RE). In this study, to prove our hypothesis, we selected 12 cases from a series of 51 bronchogenic carcinomas. In these 12 cases, we examined the ability of the expressed mt p53 to bind the MDM2-p53RE and correlated the findings with MDM2 expression. Furthermore, we constructed four of these p53 mutants and studied their transactivation properties by co-transfecting them with a reporter plasmid carrying MDM2-p53RE in the p53 null non-small-cell lung carcinoma cell line (NSCLC) H1299. We observed mutant p53 protein DNA-binding activity, which depended on the nature and the position of the amino acid substitution. The fact that the cases with DNA-binding activity were accompanied with MDM2 protein isoforms’ overexpression is indicative of a ‘gain of function’ phenotype. This hypothesis was enforced by the findings of the transfection experiments, which revealed that certain p53 mutants enhanced the expression of the luciferase reporter gene either directly or indirectly via a dominant positive effect on the wild-type p53. In conclusion, this work is one first attempt to examine if the deregulation of the p53/MDM2 autoregulatory feedback loop is due to novel properties of certain p53 mutants in the specific environment of a subset of bronchogenic carcinomas