New treatment strategies for HPV-positive head and neck cancer

Epidemiological studies show an increasing incidence of human papilloma virus-associated oropharyngeal cancer. HPV-positive head and neck squamous cell carcinoma (HNSCC) is recognized as a special subgroup of HNSCC. Because HPV-positive patients are often younger and have an outstanding prognosis, long-term toxicities of therapy have become an important issue. Current clinical trials focus on a reduction of treatment-related toxicity and the development of HPV-specific therapies. New treatment strategies include a dose reduction of radiotherapy, the use of cetuximab instead of cisplatin for chemoradiation and transoral robotic surgery (TORS). Increasing comprehension of the molecular background of HPV-associated HNSCC has also lead to more specific treatment attempts including immunotherapeutic strategies. Whereas recently published data shed light on immune mechanisms resulting in a tolerogenic niche for HPV and HPV-associated HNSCC, other studies focus on specific vaccination of HPV-positive HNSCC. This study will summarize current therapy approaches and illustrate ongoing clinical trials in the field of HPV-positive HNSCC.     

Assay-based response evaluation in head and neck oncology: requirements for better decision making

This article gives an overview on different current strategies of assay-based response evaluation in head and neck squamous cell carcinomas (HNSCC) and critically summarizes their role and needs for future clinical evaluation. Due to a growing amount of data of phase III clinical trials of multimodality treatment options for HNSCC, treatment planning in regard to optimal outcome is becoming an interdisciplinary challenge. New concepts such as induction chemotherapy with bi- or ternary combinations of chemotherapeutics, integration of targeted therapies, concurrent and sequential chemoradiation concepts, and multimodality-based organ preservation strategies strongly compete with traditional definitive surgical procedures. Moreover, the outcome is difficult to predict due to heterogeneity of a tumor’s response, impaired late functional outcome, and increased late toxicity if simultaneously applied to radiation. Retrospectively looking at non-responders with tumors classified as resectable, primary surgery is very likely to have achieved better results, since chemoradiation causes a high degree of early and late toxicities leading to extremely complicated terms and conditions in surgery following current multimodal therapeutic strategies. Unfortunately, predictive information on response characteristics of a given tumor before starting the therapy is not available in daily routine, although heterogeneity in response of a given tumor entity to treatments has been known for decades. Therefore, current therapy strategies for HNSCC still have to ignore this fact, creating an urgent need for the development of proper predictive assays. There are interesting clinical observations showing that response on induction chemotherapy may predict the outcome after radiotherapy. Some trials use this empiric phenomenon to pre-select non-responders for primary surgical treatment avoiding severe salvage complications after failure of complete chemoradiation treatment. Moving one step further, recent literature and our own investigations implicate that response evaluation of the individual patient’s HNSCC in a suitable ex vivo assay just before starting the treatment is mature for clinical research. To this end, essential needs and hints are addressed and discussed.     

Association Between Interleukin-6 and Head and Neck Squamous Cell Carcinoma: A Systematic Review

Interleukin-6 (IL-6) is a proinflammatory cytokine which plays an important role in several regulatory mechanisms of cancer. Moreover, experimental and clinical studies have reported that IL-6 targeted therapies might provide significant benefits for cancer treatment. The purpose of this systematic review is to evaluate IL-6 activity in patients with head and neck squamous cell carcinoma (HNSCC). A systematic review of the association between serum, saliva and tumor IL-6 and HNSCC was developed on PubMed/Medline in the publication range from January 1995 to January 2019. Our literature analysis demonstrated that overexpression and elevated serum and/or saliva IL-6 concentrations in patients with HNSCC are related to poor survival and oncological outcomes. Although there is a correlation between IL-6 concentrations and tumorigenicity, it is noteworthy that IL-6 targeted therapies are generally performed in vitro and in experimental studies. Therefore, prospective, randomized clinical trials are required that focus on IL-6 targeted therapies for the treatment of HNSCC.     

Studienergebnisse zur Primärtherapie von Kopf-Hals-Tumoren

At the annual meeting of the American Society of Clinical Oncology (ASCO) 2016, results of current trials dealing with primary therapy for head and neck squamous cell carcinoma (HNSCC) were presented. Current trials investigate in particular therapy regimens for the treatment of locally advanced HNSCC. Concomitant chemoradiotherapy (CRT) remains the standard therapy approach. Current trials focus on sequential chemoradiation with modifications in induction chemotherapy (ICT) or the subsequent CRT schedule. Studies investigating the combination of targeted therapy with the epidermal growth factor receptor (EGFR) antibody cetuximab and concomitant, sequential, or adjuvant therapy were presented. The most important trials are summarized in this article.     

Anti-angiogenesis - a therapy concept in the treatment of head and neck carcinomas? A review

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy that is now the sixth most common neoplasm in the world. Despite numerous advances in treatment, the long-term survival has remained the same for the last 25 years. Angiogenesis has been shown to be important for HNSCC tumour growth and metastasis. Therefore, inhibitors of angiogenesis are a new class of anti-neoplastic substances that might be a powerful complement to conventional therapy in HNSCC. MATERIAL AND METHODS: The role of angiogenesis in HNSCC as well as preclinical and clinical trials concerning inhibitors of tumor-angiogenesis are discussed here. RESULTS: Many of the investigated angiogenesis inhibitors demonstrated anti-tumor effects in preclinical and clinical trials. In a few cases, partial remission was observed. CONCLUSIONS: Anti-angiogenic therapy will undoubtly have the potential to change standard tumor therapies. Some anti-angiogenic substances appear to be promising candidates for a clinical use in the therapy of HNSCC.     

Current aspects of targeted therapy in head and neck tumors

This review focuses on the current and upcoming options of targeted therapy (biologicals) in head and neck squamous cell carcinoma (HNSCC) with special regard to conceptual integration in future strategies. Epidermal growth factor receptor (EGFR) is the most prominent candidate for therapeutic targeting because of its more than 90% expression rate in HNSCC and influence on the regulation of proliferation, apoptosis, metastasis, angiogenesis and cell differentiation. The point of view of head and neck surgeons is mainly adjusted to reach a balance between targeted, minimal ablative surgery and the evidence-based demand of oncologic accurate surgery with clear margins and, if needed, adjuvant or primary systemic chemoradiation. Therefore, the long-term effects of chemoradiation regimens, such as dysphagia, aspiration and laryngeal immobility caused by fibrosis, are just beginning to be studied and are becoming one of the major problems in the ongoing treatment of HNSCC. In this context, molecular targeting biologicals with a different toxicity profile and hopefully less late damage to functionally important tissues may open new strategies in primary and adjuvant treatment of HNSCC. Besides cetuximab and other EGFR targeting mAbs, this review focuses on receptor and non-receptor tyrosine kinase inhibitors, which further might play a role in the future treatment of HNSCC. To complete the current picture, the problem of multi drug resistance in cancer progenitor cells, targeting members of several relevant pathways and novel agents like pemetrexed and enzastaurin, are discussed in a broader sense of targeted therapy.     

The evolving role of selective neck dissection for head and neck squamous cell carcinoma

Neck dissection is an important part of the surgical treatment of head and neck squamous cell carcinoma (HNSCC). The historical concept of neck dissection implied the removal of all lymph node-bearing tissue in the neck, which began in the late nineteenth century. However, more conservative variations of neck dissection have been performed and promoted as well. Anatomic, pathologic, clinical investigations, and prospective studies have demonstrated that the lymphatic dissemination of HNSCC occurs in predictable patterns. Supported by these studies, selective neck dissection (SND), which consists of the removal of select levels of lymph nodes in the neck that have the highest risk of harboring undetected metastases, has become widely accepted in the treatment of the clinically uninvolved neck. More recently, evidence supports using SND in a therapeutic setting in selected cases of HNSCC with limited metastatic disease. Additionally, even more targeted dissections referred to as super-selective neck dissection have been explored for selected patients undergoing elective node dissection for supraglottic cancer and as an adjuvant therapy for salvage of residual lymphadenopathy confined to a single neck level following chemoradiation. In the future, the trend to tailor treatment to individual patients and to limit toxicity and morbidity may further increase the use of SND. The indications have to be guided by further research, in relation with non-surgical treatment options while optimizing oncological effectiveness.     

Current thoughts on the role of chemotherapy and radiation in advanced head and neck cancer

PURPOSE OF REVIEW: The management of advanced malignancies of the head and neck continues to be a challenging clinical problem. During the last three decades, the traditional treatments of surgery and/or radiation have not yielded significant improvements in survival in this patient population. In addition, surgery for advanced disease can create significant functional and cosmetic defects that adversely impact a patient's quality of life. Newer "organ preservation" approaches using chemotherapy and radiation are currently being studied in an attempt to improve survival while maintaining the functional integrity of the disease site. RECENT FINDINGS: Recent studies have demonstrated that for advanced head and neck squamous cell cancers, concurrent chemoradiation is superior to radiation alone for local tumor control and perhaps overall survival. With the exception of laryngeal cancer, phase III data comparing chemoradiation with surgery is lacking for most head and neck subsites. However, comparisons with historical controls suggest that chemoradiation strategies may offer improved outcomes when compared with more traditional treatment regimens. SUMMARY: This review emphasizes recent phase III trials that support the use of chemoradiation strategies in the treatment of advanced head and neck squamous cell cancers.     

免疫检查点抑制剂在复发或转移性头颈鳞癌的治疗进展

以铂类为基础的化疗联合西妥昔单抗是复发或转移性头颈鳞状细胞癌（R/M HNSCC）的标准治疗方式，然而治疗后有易复发、中位生存期短等问题。以PD-1/PDL-1单抗为主的免疫检查点抑制剂（ICIs）开始成为R/M HNSCC新的临床治疗方案，且pembrolizumab和nivolumab都已被FDA批准用于经铂类治疗失败的R/M HNSCC。现就ICIs在R/M HNSCC的临床试验进行系统汇总，并对药物的不良反应及生物标志物进行阐述，为未来在R/M HNSCC中使用ICIs提供理论基础。     

头颈部鳞状细胞癌的靶向治疗研究进展

头颈部肿瘤是常见肿瘤之一,超过95%的病理类型是鳞状细胞癌,手术与放化疗结合的综合治疗方案是头颈部鳞状细胞癌(HNSCC)的主要治疗方案,但是总体生存率并不高,主要原因是肿瘤复发和/或转移;同时复发性或转移性HNSCC常无法进行手术治疗,放化疗效果也差。靶向治疗的发现为HNSCC、特别是复发性或转移性HNSCC的治疗提供了新的方法。为了进一步认识靶向治疗的临床治疗作用,就HNSCC的靶向治疗研究进展做一综述。     

Effect of comorbidity on quality of life and treatment selection in patients with squamous cell carcinoma of the head and neck

OBJECTIVES: Comorbidity is significantly associated with diminished survival and quality of life (QOL) after treatment of head and neck squamous cell carcinoma (HNSCC). We sought to determine whether comorbidity influenced pretreatment QOL scores and treatment selection in patients with HNSCC. METHODS: The medical records of all patients diagnosed with HNSCC who participated in pretreatment QOL analysis over a 15-month period were retrospectively reviewed. Patients with a history of prior treatment for head and neck cancer, unresectable, or distant metastatic disease were excluded. The University of Washington (UW) QOL questionnaire, Performance Status Scale (PSS), and Karnofsky score were used to measure pretreatment QOL. Comorbidity was graded using the Modified Medical Comorbidity Index. RESULTS: Of 75 patients who met study criteria, 33 underwent primary surgical therapy, and 42 underwent nonoperative (radiation or chemoradiation) therapy. Treatment groups did not differ with respect to patient demographics, UW QOL scores, PSS scores, Karnofsky score, or comorbidity. Treatment groups differed significantly by disease stage and primary site. Patients with advanced stage disease (III/IV) or oropharyngeal primary tumors were more likely to undergo nonoperative treatment, compared with patients with early stage disease (I/II) or oral cavity primary tumors (P < .005). No significant association was found between comorbidity and pretreatment QOL scores. CONCLUSIONS: Comorbidity was not significantly associated with treatment selection or pretreatment QOL scores in patients with HNSCC. Location of the primary tumor and disease stage were significantly associated with treatment selection. Further studies are required to determine the effect of comorbidity on patient and tumor responses to treatment.     

Evaluation of survival of patients with locally advanced head and neck cancer treated in a single center

IntroductionEven with improved treatment outcomes with multimodality approaches, the question of what is the best initial treatment for locally advanced head and neck cancer still remains unanswered.ObjectiveTo review the overall survival of a large cohort of head and neck cancer, patients with locally advanced head and neck cancer treated in a single institution.Material and methodsWe studied a cohort of patients with locally advanced head and neck cancer treated in our institution in the last fifteen years. To gather a large sample of patients with adequate follow-up time, a cross-check between ours and Fundação Oncocentro de São Paulo databases were done. We included patients with head and neck cancer, clinical or pathological staging III or IV, treated with surgery followed by radiotherapy or surgery plus chemoradiation or radiotherapy alone or chemoradiation alone.Results796 patients with locally advanced head and neck cancer were included, 88% male, 44% age >60 years and 76% stage IV. The tumor location was the oral cavity (34%), oropharynx (27%), hypopharynx (17%) and larynx (17%). The treatment groups were chemoradiation alone (39.7%), surgery plus chemoradiation (26.3%), surgery followed by radiotherapy (18.5%) and radiotherapy alone (15.5%). Comparing the clinical variables between the treatment groups significant differences in age and clinical stage were observed. With a median follow up of 7.5 years (1–16 years), for the entire cohort, the overall survival at 5 and 10 years was 34.8% and 28%. The overall survival at 5 and 10 years was 16.7% and 12.2% for radiotherapy alone, 38.8% and 26.3% for surgery followed by radiotherapy, 28% and 16.6% for chemoradiation alone, and 37.3% and 23.2% for surgery plus chemoradiation. The staging IV (p = 0.03) and radiotherapy alone (p = 0.05), had a worst survival in multivariate analysis. Surgical groups vs. chemoradiation alone had no significant difference for overall survival.ConclusionThe present study is the largest cohort of locally advanced head and neck cancer of Brazilian patients to evaluate treatment outcomes. Although there were significant clinical differences between surgical and radiotherapy groups, surgery or chemoradiation alone as the initial treatment resulted in no significant difference in survival.     

Platinum rechallenge in recurrent head and neck squamous cell carcinoma after primary chemoradiation

ObjectiveTo evaluate platinum rechallenge efficacy and tolerance in patients presenting recurrent head and neck squamous cell carcinoma (HNSCC) after platinum-based chemoradiation.Materials and methodsWe retrospectively included all patients treated from 2007 to 2016 by platinum-based polychemotherapy for recurrence of HNSCC previously treated by primary or postsurgical platinum-based chemoradiation. The primary end-point was disease control rate (DCR) on platinum rechallenge.ResultsForty-five patients were included. Median disease-free interval (DFI) after chemoradiation was 5.7 months. DCR on platinum rechallenge was 40%. Progression-free survival at recurrence was 3.7 months and overall survival 5.0 months. DCR in patients with recurrence within 6 months of chemoradiotherapy was 47.8%. DFI > 4.5 months was associated with better DCR: 28.5% versus 54.8%; P = 0.0311.ConclusionPlatinum rechallenge provided good DCR in recurrent HNSCC after chemoradiation.     

Prognostischer Stellenwert des Hämoglobinwertes vor primärer Radiochemotherapie von Kopf-Hals-Karzinomen

The pretherapeutic hemoglobin level (Hb) has been postulated to constitute a prognostic marker for outcome after primary chemoradiation of patients with advanced cancer of the head and neck. However, this hypothesis has not been tested systematically in large study samples. In the years 1992-1997, 125 patients with advanced head and neck cancer (stages III/IV UICC) were treated with primary chemoradiation in two different prospective multicentric trials, 62 patients in trial A (phase II, 1992-1995), and 63 in trial B (phase III, 1995-1997). Beside initial Hb, other pretherapeutic parameters with potential prognostic relevance were assessed and correlated with clinical outcome after 43-months follow-up: total tumor volume (TTV; calculated in initial CT scans), tumor oxygenation (polarographic measurements with Eppendorf histography), TNM, tumor localization, age, and performance status. The evaluation of the clinical end points (progression-free and overall survival and local tumor control) revealed that Hb and TTV were independent parameters with strong predictive character of outcome after primary chemoradiation in both trials (n = 125). Bivariate analysis showed < median (13.5 g/dl) a hazard ratio of 2.1 (P = 0.002) for Hb; and > median (98 ml) a Hazard ratio of 2.0 (P = 0.006) for TTV. Severe anemia (Hb < 10 g/dl) was an adverse factor in three patients. Hypoxia was associated with poorer initial therapeutical response but was not predictive of clinical outcome. Furthermore, tumor oxygenation showed no correlation with Hb. The other parameters examined failed to show prognostic significance. Our results indicate a high prognostic value of initial Hb for outcome after primary chemoradiation in advanced head and neck cancer and imply a therapeutic benefit of Hb substitution or erythropoietin administration. We propose to test this in randomized clinical trials.     

Biology and relevance of stem cells in squamous head and neck cancer: latest insights and review of literature

The initiation, growth, recurrence and metastasis of head and neck squamous cell carcinomas (HNSCC) and other cancers have recently been related to the presence of cancer stem cells (CSC). Cancer stem cells have some characteristics in common with tissue stem cells like unlimited self renewal and the expression of stem cell factors. CSC express specific markers that vary considerably depending on tumor type or tissue of origin--the discovery of an universal marker has not yet been made. Compared to the bulk tumor mass, CSC are less sensitive to chemo- and radiotherapy and also have a lower immunogenicity. Another concept that explains the seeding of metastases is the epithelial-mesenchymal transition of CSC. CSC-targeted therapies may change the prognosis of patients with HNSCC in the future. Recent knowledge on the role of CSC in HNSCC is reviewed, and known CSC markers as well as possible therapeutic targets are described.     

单羧酸转运蛋白家族与头颈部鳞状细胞癌的研究进展

单羧酸转运蛋白家族(MCTs)参与肿瘤代谢调节,对细胞的乳酸、丙酮酸、酮体等物质起转运作用,在不同的肿瘤细胞中表达出不同的亚型。家族内的MCT1和MCT4及其伴侣蛋白CD147、葡萄糖转运蛋白GLUT-1、缺氧生物标记碳酸酐酶9(CAIX)在鼻咽癌、喉癌、口腔鳞状细胞癌等头颈部鳞状细胞癌中均发挥了重要作用。针对头颈鳞状细胞癌中MCTs不同的亚型采取靶向治疗及与其他治疗方式联合治疗以取得更好的疗效是未来的研究方向。就MCTs在头颈部鳞状细胞癌发生发展的作用机制及以MCTs作为靶点进行治疗的研究现状做综述。     

Pretreatment performance status and nutrition are associated with early mortality of locally advanced head and neck cancer patients undergoing concurrent chemoradiation

Unexpected fatal events in patients with head and neck cancers undergoing concurrent chemoradiation therapy are a clinical concern. Malnutrition, which is reported frequently in head and neck cancer patients, are associated with immunity derangement. The purpose of this study was to identify risk factors for early death of patients undergoing chemoradiation. We retrospectively analyzed the records of 194 stage III, IVA, and IVB head and neck cancer patients who were treated with chemoradiation between 2007 and 2009. We defined early death as death while receiving chemoradiation or within 60 days of treatment completion. Risk factors for early death were tested using univariate and multivariate analyses. Fourteen patients (7.2 %) experienced early death, 78.6 % of whom died of infection. Univariate analysis revealed significant correlations between early death and several pretreatment variables, including Eastern Cooperative Oncology Group performance status (PS) >1, hemoglobin <10 g/dL, albumin <3 g/dL, body mass index (BMI) <19 kg/m², and peripheral blood total lymphocyte count <700/μL. Multivariate analysis showed that PS >1, BMI <19 kg/m², and peripheral blood total lymphocyte count <700/μL were independent variables associated with early death. Poor performance status and malnutrition before chemoradiation independently predict early death in locally advanced head and neck cancer patients undergoing chemoradiation. Cautious management of head and neck cancer patients with these risk factors is required throughout chemoradiation period.     

Analytical and clinical evaluation of CYFRA 21-1 by electrochemiluminescent immunoassay in head and neck squamous cell carcinoma

This paper attempts to evaluate the clinical usefulness of CYFRA 21-1 as a serum tumour marker in patients with head and neck squamous cell carcinoma (HNSCC). The serum concentration of CYFRA 21-1 was measured utilizing a new electrochemiluminescent immunoassay (ECLIA) in 142 patients with HNSCC before and after treatment, 68 patients with benign tumours of the head and neck, and 50 healthy controls. Serum levels of CYFRA 21-1 in patients with HNSCC were significantly higher than those of benign tumours and healthy controls (p < 0.001). The diagnostic sensitivity and specificity of CYFRA 21-1 for HNSCC were 62 per cent and 100 per cent, respectively. The positive rates of CYFRA 21-1 increased with progression of HNSCC, serum CYFRA 21-1 levels were related to the tumour stage expressed by primary tumour (T) and nodal status (N) (p < 0.001), but not related to patient age, gender, smoking and drinking habit, or histopathological grade (p > 0.05). Post-treatment levels of CYFRA 21-1 in HNSCC decreased significantly (p < 0.001). Among 38 patients with clinical or radiological evidence of a recurrence during follow-up, 78.9 per cent (30 of 38) showed an increase in CYFRA 21-1. The analytical ECLIA performance for serum CYFRA 21-1 provides a new means of clinical assessment for HNSCC. The results of ECLIA suggest that the serum marker CYFRA 21-1 is valuable not only for diagnosis but also for close monitoring of patients with HNSCC.     

Positive correlation of tissue inhibitor of metalloproteinase-3 and death-associated protein kinase hypermethylation in head and neck squamous cell carcinoma

OBJECTIVES/HYPOTHESIS: Promoter hypermethylation of tumor suppressor genes is common in head and neck cancer as well as other primary cancers resulting in epigenetic gene silencing. Tissue inhibitor of metalloproteinase-3 (TIMP-3) has been shown to have promoter hypermethylation in several solid tumors, but has not been identified in head and neck squamous cell carcinoma (HNSCC). Our objective was to determine if TIMP-3 promoter was hypermethylated in HNSCC, if there was any correlation with death associated protein kinase (DAPK), a tumor suppressor whose promoter has been hypermethylated at high levels in HNSCC, and if any clinical factors influence hypermethylation of either of these genes. STUDY DESIGN: Prospective study. METHODS: Tumor samples from 124 patients with HNSCC were evaluated for promoter hypermethylation for TIMP-3 and DAPK using quantitative methylation specific polymerase chain reaction (qMSP). We compared both TIMP-3 and DAPK hypermethylation in HNSCC with each other as well as with other clinical variables. RESULTS: We found that TIMP-3 was hypermethylated in approximately 71.8% of the tumor samples and DAPK was hypermethylated in 74.2%. The presence of TIMP-3 and DAPK promoter hypermethylation was significantly higher than in control specimens. More importantly, TIMP-3 and DAPK hypermethylations in these samples were highly correlated with a concordance of 78% (P < .001). DAPK was also correlated with current alcohol consumption (P < .028), but neither TIMP-3 nor DAPK hypermethylation was significantly correlated with other clinical variables or with survival. CONCLUSION: TIMP-3 promoter hypermethylation is elevated in HNSCC and is highly correlated with DAPK hypermethylation, implying a functional relationship between these genes.     

The ARF-p16 gene locus in carcinogenesis and therapy of head and neck squamous cell carcinoma

OBJECTIVES/HYPOTHESIS: We have identified families with a high incidence of tumors including head and neck squamous cell carcinoma (HNSCC). The occurrence of melanoma in these kindreds suggested that the ARF-p16 gene may be involved in carcinogenesis. We wished to determine the gene defect associated with the familial predisposition to HNSCC and to determine whether restoration of the gene may have therapeutic benefit. STUDY DESIGN: Translational molecular research. METHODS: Molecular techniques were used to identify mutations of the ARF-p16 gene from the affected families and to test the activity of p16 and ARF mutants. In additional, HNSCC tumor tissue was analyzed to determine whether the wild-type p16 allele was lost or maintained. ARF-expressing adenoviruses were created, and their effect on HNSCC cell lines and normal head and neck epithelial cells was determined. RESULTS: Mutation of the ARF-p16 gene was found in two families with predisposition to develop HNSCC. Independent mutations detected in the germline DNA of both families inactivated p16, but not ARF, and the inactive mutant p16 allele segregated with disease within both families. The wild-type p16 allele was lost in HNSCC tumor tissue from both families. The efficacy of ARF in treatment of HNSCC was found to depend on retention of p53 activity within HNSCC tumor cells. Remarkably, ARF expression was found to kill cells, depending on loss of retinoblastoma activity. Because loss of retinoblastoma activity is nearly universal in tumors, ARF killed tumor cells that retained p53, but ARF spared normal cells. CONCLUSIONS: Our results support the recognition of a new clinical entity of familial head and neck cancer. We have shown that this syndrome is associated with inactivating mutations of the p16 gene that these mutations segregate with disease in two described families. Loss of the wild-type p16 allele in HNSCC tissue from both families strongly supports the role of the mutant p16 in carcinogenesis. We have also investigated the therapeutic utility of the alternate reading frame product of the p16 gene, ARF. The finding that ARF kills cells depending on loss of retinoblastoma activity and retention of p53 suggests that ARF may be effective in treatment of roughly 50% of head and neck cancers while sparing normal cells. Recognition of p16 mutations as an etiological factor in familial HNSCC provides an accessible tool for diagnosis of this syndrome. Clinical acceptance of familial head and neck cancer will ensure that patients are appropriately diagnosed and managed.