RESUMO
OBJECTIVE/HYPOTHESIS: We examined whether p53 gene mutations were predictive of clinical behavior in laryngeal cancer. STUDY DESIGN: Retrospective study of 45 patients with laryngeal cancer from 1985 to 1997. METHODS: DNA was extracted from tumor tissue and subject to polymerase chain reaction single-strand conformational polymorphism (PCR-SSCP) as well as DNA sequencing. The clinical outcome was correlated to the presence or absence of a p53 mutation. RESULTS: The p53 gene was analyzed by direct DNA sequencing and was found to be mutated in 33% (15/45) of patients. The presence of a p53 mutation was associated with a significant improvement in overall survival (80% vs. 43%, P < .03) and a trend toward improved disease-free survival (87% vs. 60%, P = .08). When other prognostic factors were adjusted, multivariate analysis revealed a trend toward improvement in overall survival as well as disease-free survival. CONCLUSION: Depending on the location of a p53 mutation, the suppressive functions or clinical outcome may or may not be affected. Fifty-three percent of mutations were detected in nonconserved regions as opposed to 17% as reported in colon cancer. In colon cancer, mutations in conserved regions of the p53 gene predicted a poorer survival, whereas nonconserved gene mutations were not predictive. In our group of patients. p53 mutations predicted a better prognosis, which may be due to a large proportion of mutations that lie within nonconserved areas. The predictive power of p53 gene mutations may depend on functional loss and inactivation of highly conserved areas and must be tested in a prospective trial.
Assuntos
Análise Mutacional de DNA , Neoplasias Laríngeas/genética , Proteína Supressora de Tumor p53/genética , Adulto , Idoso , Sequência de Aminoácidos/genética , Sequência Conservada/genética , Feminino , Humanos , Neoplasias Laríngeas/mortalidade , Neoplasias Laríngeas/patologia , Laringectomia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida , Repetições de Trinucleotídeos/genéticaRESUMO
Dopamine receptor isoforms were examined in the cochlea of the CBA(J) mouse by RT-PCR analysis and nucleotide sequencing, utilizing primers specific for known dopamine receptor isoforms. Cochlear cDNA sequences corresponding to dopamine D2(long) and D3 receptors were amplified, whereas those representing D1A, D1B, D2(short), and D4 were not detected. Utilizing quantitative competitive PCR analysis, relative levels of dopamine receptor transcripts were found to be 0.002, 0.014, 0.016, and 1.000 for D2(long) cochlea, D3 cochlea, D3 brain, and D2(long) brain, respectively. In the context of previously published findings, the current work provides key quantitative evidence necessary to establish that dopamine is a neurotransmitter in the auditory inner ear.
