Head and neck squamous cell growth suppression using adenovirus-p53-FLAG: a potential marker for gene therapy trials.

The recombinant wild-type p53 adenovirus has been proven effective against the growth of human head and neck squamous cell cancer (SCCHN) cell lines iir vitro and in a nude mouse model. The addition of a FLAG peptide sequence was used in this study, along with the p53 adenovirus vector as a marker of the site of the gene therapy activity. It provides clear evidence of the exogenous gene product within the transduced carcinoma cells. No alterations in transcription or translation of the p53 gene product were noted with the addition of the FLAG sequence to the original p53 adenovirus vector. Immunohistochemical analysis displayed simultaneous expression of the p53 and FLAG proteins in the infected cells. The p53 protein remained localized to the nucleus, whereas the FLAG protein was additionally noted in the cytoplasm. In vitro growth suppression assays and in vivo microscopic residual tumor model experiments in nude mice showed a similar tumoricidal effect with the p53-FLAG adenovirus vector to that with the previously studied p53 adenovirus vector without the addition of the FLAG sequence. We conclude that the addition of the FLAG octapeptide sequence allows identification of those cells that have been affected by the molecular therapy independent of the endogenous gene expression of the cells. This novel molecular tracer may prove useful in characterizing infection efficiency and in gene therapy trials.

Prognostic factors affecting outcome in lower gingival carcinoma.

Squamous cell carcinoma of the lower gingiva is a rare lesion that frequently invades the mandible. To determine the factors that affect local disease control and overall survival, a retrospective review of 155 previously untreated patients was performed. Primary lesions larger than 3 cm (P = .021) and persistently disease-positive surgical margins (P = .027) were found to be associated with decreased local control rates. Survival was adversely affected by advanced T stage (P = .001), positive initial and final surgical margins (P = .004), mandibular invasion (P = .014), and cervical metastases (P<.001). Extent of mandibular resection, tumor extension beyond the lower gingiva, recent dental extractions in the region of the primary, perineural invasion, and histologic grade did not affect local control or survival. Although lower gingival carcinoma tends to involve the mandible, our findings indicate that tumor size is more important than mandibular invasion in predicting local disease control. Larger tumors that have a greater propensity for local recurrence and poorer survival require a more extensive surgical resection.

Lower gingival carcinoma. Clinical and pathologic determinants of regional metastases.

OBJECTIVE: To determine which clinical and pathologic features are associated with regional metastases in patients with lower gingival squamous cell carcinoma. PATIENTS AND METHODS: The medical charts of 155 previously untreated patients seen between 1970 and 1990 were retrospectively analyzed. All patients underwent surgical resection of the primary tumor. In addition, 66 patients underwent elective neck dissection, while a therapeutic neck dissection was performed in 28. Sixty-one patients who had clinically N0 neck disease did not undergo treatment of the cervical lymphatics. RESULTS: T stage (P = .01), radiologic (P = .03) or histologic (P = .01) evidence of mandibular invasion, and decreased tumor differentiation (P = .004) significantly correlated with the presence or evolution of regional metastases. In addition, tumors involving the symphyseal region were associated with an increased incidence of nodal metastases, although the relationship did not achieve statistical significance (P = .08). Occult regional disease was found in 18% of patients who underwent elective neck dissection, and the presence of metastases was pathologically confirmed in 68% who underwent a therapeutic dissection. Six patients with clinically N0 neck disease did not undergo elective dissection and later developed regional metastases. In all patients, survival was adversely impacted by the presence or later development of regional metastases (P < .001). Two- and 5-year survival rates for patients with no cervical metastases were 0.91 and 0.85, respectively, while for those with cervical metastases, the survival at 2 and 5 years declined to 0.72 and 0.59. More importantly, the 2- and 5-year survivals of patients with clinically N0 necks who were found to have lymph node metastases histologically after neck dissection were 1.00 and 0.78. This contrasts with the 0.50 survival rate at 2 and 5 years for those who did not undergo elective dissection and later developed cervical metastases (P = .36). CONCLUSIONS: Patients with adverse clinical and pathologic features, even in the absence of demonstrable neck disease, are at risk for harboring regional metastases. Elective treatment of the cervical lymphatics should be considered for patients with primary tumors that overlie the mandibular symphysis, moderately or poorly differentiated tumors, or radiographic or histologic evidence of mandibular invasion.

Gene therapy for head and neck cancer. Comparing the tumor suppressor gene p53 and a cell cycle regulator WAF1/CIP1 (p21).

OBJECTIVE: To compare the efficacy of the tumor suppressor gene wild-type p53 with that of cell-cycle regulator WAF1/CIP1 as single-agent gene therapy for squamous cell carcinoma of the head and neck. EXPERIMENTAL METHODS AND DESIGN: Recombinant cytomegalovirus-promoted adenoviruses containing the wild-type p53 or WAF1/CIP1 (p21) genes were transiently introduced into squamous cell carcinoma of the head and neck cell lines. Standard Western blot analysis was used to determine expression in these cells of the proteins encoded by these genes. A nude mouse xenograft model of squamous cell carcinoma of the head and neck was used to investigate the in vivo efficacy of the repeated gene therapy interventions. RESULTS: Western blot analysis showed marked induction of the WAF1/CIP1 tumor suppressor gene product by both the p21 adenovirus and the wild-type p53 adenovirus (as a secondarily transcribed product). In vitro growth curves demonstrated that the wild-type p53 adenovirus significantly inhibited cell growth in these cell lines, whereas direct induction of the p21 gene product did not. Repeated infection with wild-type p53 adenovirus significantly reduced the size of established subcutaneous tumors, whereas infection with a replication-defective viral control did not. CONCLUSION: Wild-type p53 adenovirus exhibits substantial in vitro and in vivo tumor suppressor activity in squamous cell carcinoma of the head and neck cell lines. This tumor suppression is not a function of the induced WAF1/CIP1 (p21) transcriptional product. Further studies are required to investigate the potential for induction of apoptosis by gene therapy.

Neuroendocrine neoplasms of the larynx.

Neuroendocrine neoplasms of the larynx are a rare group of tumors that include carcinoid tumor, atypical carcinoid tumor, and small cell carcinoma. These neoplasms pose interesting diagnostic, prognostic, and therapeutic dilemmas, and they are, as a whole, aggressive tumors with a tendency for local and distant spread. The authors of this study examined six new cases of laryngeal neuroendocrine neoplasms. One case manifested itself as a primary atypical carcinoid tumor and caused a "carcinoid syndrome." The remaining five cases were small cell carcinomas of the larynx. Histologic, immunocytochemical, DNA flow cytometric, and p53 studies were performed on all cases. The expression of neuron-specific enolase and chromogranin were the most useful markers in this group of tumors. Overexpression of p53 protein was present in the majority of cases, including the atypical carcinoid tumor. The implications of these studies for diagnosis, classification, and treatment are discussed.

Comparison of crossed and uncrossed acoustic reflex latencies.

OBJECTIVE: To compare morphologies of crossed and uncrossed acoustic reflex waveforms. DESIGN: Subjects were 12 young adults with normal hearing. A signal-averaging technique was used to compare onset and offset latencies of crossed and uncrossed acoustic reflex waveforms when maximum amplitudes were matched. RESULTS: Onset latency was similar for the two modes, but offset latency was significantly longer for the crossed reflex. Further, in individual subjects the difference between crossed and uncrossed offset latencies was inversely proportional to maximum reflex amplitude. CONCLUSION: Results emphasize the complex interaction between amplitude and latency characteristics of acoustic reflex waveform.