Jay O. Boyle

Molecular assessment of histopathological staging in squamous-cell carcinoma of the head and neck.

BACKGROUNDnSurgical oncologists rely heavily on the histopathological assessment of surgical margins to ensure total excision of the tumor in patients with head and neck cancer. However, current techniques may not detect small numbers of cancer cells at the margins of resection or in cervical lymph nodes.nnnMETHODSnWe used molecular techniques to determine whether clonal populations of infiltrating tumor cells harboring mutations of the p53 gene could be detected in histopathologically negative surgical margins and cervical lymph nodes of patients with squamous-cell carcinoma of the head and neck.nnnRESULTSnWe identified 25 patients with primary squamous-cell carcinoma of the head and neck containing a p53 mutation who appeared to have had complete tumor resection on the basis of a negative histopathological assessment. In 13 of these 25 patients, molecular analysis was positive for a p53 mutation in at least one tumor margin. In 5 of 13 patients with positive margins by this method (38 percent), the carcinoma has recurred locally, as compared with none of 12 patients with negative margins (P = 0.02 by the log-rank test). Furthermore, molecular analysis identified neoplastic cells in 6 of 28 lymph nodes (21 percent) that were initially negative by histopathological assessment.nnnCONCLUSIONSnAmong specimens initially believed to be negative by light microscopy, a substantial percentage of the surgical margins and lymph nodes from patients with squamous-cell carcinoma of the head and neck contained p53 mutations specific for the primary tumor. Patients with these positive margins appear to have a substantially increased risk of local recurrence. Molecular analysis of surgical margins and lymph nodes can augment standard histopathological assessment and may improve the prediction of local tumor recurrence.

Association between cigarette smoking and mutation of the p53 gene in squamous-cell carcinoma of the head and neck.

BACKGROUNDnAlthough epidemiologic studies have long associated tobacco and alcohol use with the development of squamous-cell carcinoma of the head and neck, the molecular targets of these carcinogens have yet to be identified. We performed a molecular analysis to determine the pattern of mutations in the p53 gene in neoplasms from patients with squamous-cell carcinoma of the head and neck and a history of tobacco or alcohol use.nnnMETHODSnSequence analysis of the conserved regions of the p53 gene was performed in tumor samples from 129 patients with primary squamous-cell carcinoma of the head and neck. We then used statistical analysis to identify any patient characteristics associated with mutation of the p53 gene.nnnRESULTSnWe found p53 mutations in 42 percent of the patients (54 of 129). Fifty-eight percent of the patients who smoked cigarettes and used alcohol (37 of 64; 95 percent confidence interval, 45 to 70 percent), 33 percent of the patients who smoked but abstained from alcohol (13 of 39; 95 percent confidence interval, 19 to 50 percent), and 17 percent of the patients who neither smoked nor drank alcohol (4 of 24, 95 percent confidence interval, 5 to 37 percent) had p53 mutations (P = 0.001). (Two patients used alcohol but did not smoke, and neither had a p53 mutation.) Furthermore, 100 percent of the mutations in the patients who neither drank nor smoked occurred at sites containing cytidine phosphate guanosine dinucleotides (potentially representing endogenous mutations) within the p53 gene (5 of 5 mutations; 95 percent confidence interval, 48 to 100 percent), whereas only 23 percent of those in cigarette smokers consisted of such changes (12 of 53 mutations; 95 percent confidence interval, 12 to 36 percent; P = 0.001).nnnCONCLUSIONSnIn our study, a history of tobacco and alcohol use was associated with a high frequency of p53 mutations in patients with squamous-cell carcinoma of the head and neck. Preliminary evidence linked cigarette smoking to p53 mutations at nonendogenous mutation sites. Our findings suggest a role for tobacco in the molecular progression of squamous-cell carcinoma of the head and neck and support the epidemiologic evidence that abstinence from smoking is important to prevent head and neck cancer.

Gene mutations in saliva as molecular markers for head and neck squamous cell carcinomas.

BACKGROUNDnCancer is caused by the accumulation of mutations that activate proto-oncogenes and inactivate tumor suppressor genes. The result is a clonal expansion of genetically identical daughter cells that eventually become clinical malignancies. The specific mutations acquired by the progenitor cell are like a fingerprint carried by each cell of the tumor. These mutations can serve as very specific markers for the presence of tumor cells in a background of normal cells.nnnMETHODSnMutations in the p53 gene recovered from head and neck squamous cell carcinomas were sequenced, and these altered DNA sequences were used retrospectively as tumor-specific genetic markers for cancer cells in the patients saliva. Cloned p53 sequences amplified by the polymerase chain reaction from DNA extracted from banked preoperative saliva specimens were screened for the presence of tumor-specific mutations using radiolabeled oligonucleotide probes.nnnRESULTSnWe identified tumor-specific mutations in preoperative saliva samples of 5 of the 7 patients evaluated (71%).nnnCONCLUSIONSnThese results suggest a potential for clinical applications of this novel approach to cancer detection using gene mutations as molecular markers for carcinomas.

Clinical Nodal Stage Is an Independently Significant Predictor of Distant Failure in Patients With Squamous Cell Carcinoma of the Larynx

Objective To determine the impact of clinical nodal stage on distant metastasis (DM) in patients with squamous cell carcinoma of the larynx (SCCL). Methods Six hundred sixty-two previously untreated SCCL patients treated at a tertiary care cancer center from January 1984 to December 1998 were eligible for analysis. The end point of interest was development of DM following treatment. Distant metastasis-free survival (DMFS) was calculated by the Kaplan-Meier method; predictors of outcome were identified by univariate and multivariate analysis. The primary tumor site was glottic in 55%, supraglottic in 40%, and trans/sub glottic in 5%; 40% had locoregionally advanced (stage III/IV) tumors. At initial presentation, 25% of patients (12% N1, 11% N2, and 2% N3) had clinically metastatic nodes. Results DM were recorded in 67 patients (10%; lung, 45%; soft tissue, 13%; bone, 10%; multiple sites, 28%). The median time to DM was 18 months (range, 1–109). With a median follow-up of 60 months, the 5-year DMFS was 88%. Even after accounting for the type of index treatment, the only significant predictor of worse DMFS on multivariate analysis was a higher clinical N stage (P < 0.0001). The relative risk for DM was 0.5 (95% CI, 0.2–1.4; P = NS) for cN1, 3.2 (95% CI, 1.7–5.9; P < 0.0001) for cN2, and 7.5 (95% CI, 3.1–17.9; P < 0.0001) for cN3 disease compared with clinically N0 patients. Conclusion Regardless of the index treatment modality, primary tumor site, or T stage, a higher clinical N stage at the time of presentation independently and significantly increases the risk of DM in patients with SCCL.