Tumor markers in squamous cell carcinoma of the head and neck: clinical effectiveness and prognostic value.

Despite recent advances in tumor surgery and multimodal treatment regimens the prognosis of squamous cell carcinomas of the head and neck is still relatively poor and has shown only slow progress. Additional clinical and biological factors are therefore urgently needed that aid tumor diagnosis, early detection of tumor recurrences, prediction of the results of therapeutic interventions, and identification of subsets of patients with unfavorable outcome during follow-up. A tumor marker should fulfill the criteria of specificity and clinical effectiveness. So far none of the known serological and biological markers fits all these criteria. Although some biological markers can be determined serologically without the need for tumor tissue, their low specificity limits their applicability to early detection of tumor recurrences during follow-up. A large number of molecular or genetic markers have been examined in squamous cell carcinomas of the head and neck. All of these are controversial regarding their prognostic value and clinical effectiveness. UICC tumor stage and patient's age and performance still remain the basis for therapeutic decisions. Further search for more sensitive and specific markers is needed to improve individual treatment and prognostic statements.

The putative tumor suppressor BIN1 is a short-lived nuclear phosphoprotein, the localization of which is altered in malignant cells.

BIN1 is a putative tumor suppressor that was identified in a genetic screen for polypeptides that interact with the MYC oncoprotein. Using a set of six monoclonal antibodies, we identified and examined biochemical features and localization of cellular BIN1. Epitope mapping indicated that a putative nuclear localization motif and the MYC-binding domain were among the regions recognized by five antibodies. In immunoprecipitation and Western analyses, cellular BIN1 was identified in human and rodent cells as a monomeric phosphoprotein of M(r) approximately 70,000. Pulse-chase experiments showed that BIN1 was short-lived, with a half-life of approximately 2 h. Cell immunofluorescence experiments revealed overlapping but unique nuclear localization patterns distinguished by two different antibodies. In normal cells, BIN1 was predominantly nucleoplasmic but was also present in a subnuclear compartment. Conversely, in a panel of tumor cells that expressed BIN1, the predominant localization was the subnuclear compartment. Taken together, the results suggested that the antibodies recognized different isoforms or conformations of BIN1, the localization of which varied between normal and tumor cells. This study will facilitate further analysis of the structure and regulation of BIN1 in normal and malignant cells.

Genetic factors in lung disease. Part II: Lung cancer and angiotensin converting enzyme gene.

The recent progress in molecular biology has led to the elucidation of pathogenesis of lung cancer. The development of a lung cancer requires multiple genetic changes, consisting of the activation of oncogenes, including the K-ras and myc genes, and of inactivation of tumour suppressor genes, including the Rb, p53 and CDKN2 genes. Knowing the specific genes undergoing such changes should be useful as biomarkers for the early detection of cells destined to become malignant. Moreover, such genetic changes could be targets of newly designed drugs and gene-based therapy. Although the angiotensin I-converting enzyme was originally discovered in equine plasma, it has been recognized in various organs and cells other than vascular endothelial cells. This enzyme is also known to have wide substrate specificity to many peptides. The definite roles of angiotensin converting enzyme (ACE) in the respiratory system are largely unknown. Recent progress in molecular biology of the ACE, however, gives us a good chance to look over the significance of ACE in respiratory diseases as well as cardiovascular disorders. In this review, we show the recent advances in the basic studies of the ACE and refer to its clinical application.

Apoptosis y proliferación celular en infecciones por el virus Herpes humano 6 (HHV-6). Mecanismos de regulación a través de interacciones de p53, bcl-2, ras y p21WAF / Apoptosis and celular proliferation in human herpes virus 6 (HHV-6) infection. Mechanism as of regulation by interactions of p53, bcl2, ras and p21WAF

Se analizaron inmunohistológicamente líneas de cultivo celular infectadas con el HHV-6: HSB2-células T inmaduras y HDLM2-células de Hodgkin, así como ganglios linfáticos de pacientes con enfermedad de Hodgkin y linfadenitis de Kikuchi-Fujimoto (LKF) en relación a la expresión de los productos oncógenos/antioncógenos p53, bcl-2, ras y p21WAF. Se comprobó la proliferación celular inmunohistológicamente mediante anticuerpos contra PCNa (antígeno nuclear de proliferación celular) y la apoptosis se investigó en cortes finos de tejido ganglionar, analizando el ADN fragmentado con marcación final in situ. La LKF mostró alta incidencia de focos de células muertas (linfadenitis histiocítica necrozante), mientras que en la enfermedad de Hodgkin se observó proliferación celular. Con las técnicas utilizadas no se logró mostrar diferencias significativas en la expresión de ADN viral no de antígenos en las líneas celulares, ni en las biopsias de enfermedad de Hodgkin y de LKF. Las células HDLM2 con mejor viabilidad posterior a la infección con HHV-6 y un grado de apoptosis inferior, mostraron una expresión de p53 y de PCNA mucho menor que las células HSB2. Las biopsias de LKF no expresaron p53; ras se observó en menores células que en la enfermedad de Hodgkin y la positividad de PCNA fue tres veces mayor en enfermedad de Hodgkin en comparación con LKf. Sin embargo el bcl-2 se observó con mayor frecuencia en LKF que en enfermedad de Hodgkin. Los resultados no son de fácil interpretación; los datos sugieren la implicación de otros factores exógenos (por ejemplo, citoquinas y factores de crecimiento) en el mecanismo regulatorio de la proliferación celular y de la apoptosis, ambas inducidas probablemente por virus

[Correlation between p-53 expression and clinical resistance in testicular cancer]. / A p-53 expresszió és a klinikai rezisztencia összefüggésének vizsgálata hererákokban.

One of the most common cellular gene which negatively regulates the cell cycle, thus functioning as tumour suppressor gene, is the p-53 gene. The presence of this mutated gene has been correlated with, the aggressiveness of several malignant neoplasmas. Expression of the p-53 gene product protein was screened in 55 untreated human germ cell testicular tumours, furthermore a relationship between p-53 expression and clinical resistance was investigated. Using monoclonal antibody and immunoenzyme staining elevated p-53 level could be demonstrated in nuclei of embryonal carcinoma (84%) and seminoma components (56%). Most of the choriocarcinoma cases showed positive staining. Teratomas expressed this antigen negatively or scarcely. In seminomas the highest level of p-53 was stated in stage I. In contrast the opposite tendency could be demonstrated in embryonal carcinomas where p-53 was ++ positive in stage III. Between the high level of p-53 and clinical resistance a converse correlation could be stated because the resistant tumours expressed no or low, the sensitive tumours high level of p-53 protein (P 0.01). These results suggest that elevated p-53 expression could be a prognostic marker of sensitivity in testis cancer.

Potential immunogenicity of oncogene and tumor suppressor gene products.

The immunogenicity of viral oncoproteins has been established beyond doubt. Cytotoxic T lymphocytes directed against viral oncogene products can eradicate large established tumor masses. This stage has not yet been reached for cellular oncogene and tumor suppressor gene products, but T cells have been raised against MHC-binding peptides encoded by both mutant and wild-type alleles of the ras oncogene and the p53 tumor suppressor gene. In addition, T cells specific for joining region peptides of abnormal fusion proteins resulting from chromosome translocation in tumor cells have been generated. Some of these peptides are processed in cells infected with, for example, vaccinia-ras, but direct anti-tumor effects of peptide specific T lymphocytes remain to be demonstrated.

[Immunochemical evidence of a mutated p53 protein expressed in human colorectal adenocarcinoma]. / Mise en évidence immunochimique de l'expression d'une protéine p53 mutée dans les adénocarcinomes colorectaux humains.

Evidence is accumulating that the p53 anti-oncogene is a key gene in the genesis of carcinoma in human colon and rectum. Although mutations of the p53 gene have been shown to be frequent, the protein was present in only approximately 50 percent of specimens examined. However only one monoclonal antibody recognizing an epitope present on wild-type p53 had been used. We studied the p53 expression in a series of 16 colorectal carcinoma specimens using 3 different monoclonal antibodies (pAb 421, 1801, 240). Specific immunofluorescent staining was quantified by dual parameter (DNA/p53) flow cytometry. Two different types of preparations were compared in order to verify the conservation of the antigen. Nuclear suspensions prepared from frozen tumor fragments were shown to produce results equivalent to those of whole cell preparations originating from fresh surgical specimens. The p53 protein was detected in 9 of the 16 cancers with pAb 421 and 240 monoclonal antibodies (8 of which were also positive for pAb 1801 antibody). Four additional tumors were considered positive for pAb 240 antibody alone. Overall, 13/16 cancer specimens were shown to present immunoreactivity for pAb 240 antibody. Topography of staining was investigated by immunohistochemistry with peroxidase methods. Eight cases were informative, 6 of which presented nuclear staining compatible with the cytometry results. There was one discordant case i.e. pAb 240 antibody being positive on cytometry and entirely negative on immunohistochemistry. This small series allowed us to show that 81 percent of tumor samples stained with monoclonal antibody pAb 240, considered to be specific to mutated protein, and that some tumors express a p53 protein which is not detected with terminal sequence-specific antibodies.