Le peptide hCAP18/LL-37, une partie de la défense immunitaire innée, a maintenant été reconnu comme multifonctionnelle pour les cellules eucaryotes. Nos études démontrent sa contribution au développement du cancer, montrant qu'il est surexprimé dans la plupart des tumeurs mammaires humaines, active la signalisation la famille de ERBB et augmente le potentiel métastatique des cellules cancéreuses du sein. Notre comparaison des deux lignées du cancer du sein n'a pas révélé de récepteurs communs, mais une structure peptidique identiques mais de chiralité différente est pré requis pour le peptide dans toutes ses activités. Nous émettons l'hypothèse que LL-37 active indirectement des récepteurs transmembranaires en se liant à la membrane cellulaire. Des peptides tronqués dérivés de LL-37 inhibent ses activités et peuvent aider à concevoir une future thérapie anticancéreuse. / The peptide hCAP18/LL-37, part of the innate immune defense, has now been recognized as multifunctional for eukaryotic cells. Our studies demonstrate its contribution to cancer development, showing that it is overexpressed in most human breast tumors, activates ERBB signaling and increases the metastatic potential of breast cancer cells. Our comparison on two breast cancer lines did not reveal any common receptors but identical structural prerequisites for the peptide in all its activities. We hypothesize that LL-37 indirectly activates transmembrane receptors by attaching to the cellular membrane. Truncated derivatives inhibit its activities and may help to design a future anticancer therapy.

INTRODUÇÃO: O tratamento padrão do câncer do colo uterino é a histerectomia radical para doença inicial e quimio-radioterapia para doença avançada. A radioterapia após a histerectomia radical tem impacto em ganho de sobrevida caso hajam fatores de risco histopatológicos para recidiva. Portanto, a busca de marcadores preditores de radiossensibilidade torna-se importante para a individualização do planejamento terapêutico. O HER-2/ErbB-2 faz parte da família de proteínas ErbB que formam um grupo de receptores de membrana e tem um papel crítico no controle de diversas funções celulares básicas como diferenciação, proliferação, migração e sobrevida celular. A ação do NF-B na carcinogênese pode ocorrer através da regulação da apoptose e controle do ciclo celular. Para ativação do NF-B é necessário a enzima quinase IKK e a atividade do NF-B foi relacionada com resistência tumoral a quimioterapia e radioterapia. A via PI3K/Akt mediada pela hiperexpressão de HER-2 pode estar envolvida na ativação do NF-B. Os objetivos foram: a) avaliar os padrões de expressão imunoistoquímica de HER-2, NF-B-p65, NF-B-p50 e IKK em pacientes portadores de câncer do colo uterino submetidos à radioterapia; b) avaliar o status do gene HER2 através de FISH; c) avaliar o papel da expressão imunoistoquímica de NF-B-p65, NF-B-p50, IKK e HER-2 como fator prognóstico para sobrevida livre de doença e sobrevida global. MATERIAIS E MÉTODOS: Trata-se de estudo retrospectivo que avaliou uma série de 32 pacientes portadores de câncer do colo do útero submetidos a tratamento com radioterapia seguido de histerectomia no período de janeiro de 1992 a junho de 2001. RESULTADOS: A idade mediana foi 45 anos (22-67). Um paciente apresentava-se no estádio IB2 (FIGO) e 31 (96,9%) estádio IIB. Todos os pacientes foram submetidos à teleterapia e braquiterapia com alta taxa de dose com caráter neoadjuvante à histerectomia radical (HR). Dezesseis (50%) pacientes apresentaram doença residual após radioterapia. O tempo de seguimento mediano foi de 73,5 meses. A sobrevida global da amostra foi de 66,5% em 5 anos. As expressões imunoistoquímicas de NF-B-p65 e NF-B-p50 em citoplasma nos tumores primários foram encontradas em respectivamente 90,6% e 96,9% dos casos. As expressões de NF-B-p65 e NF-B-p50 em núcleo nos tumores primários 59,4% dos casos em ambos. As expressões de NF-B-p65 e NF-B-p50 em citoplasma nos tumores residuais após tratamento com radioterapia foram encontradas 50% dos casos em ambos. A expressão em núcleo de NF-B-p50 nos tumores residuais após tratamento com radioterapia foi encontrada em 75% dos casos. Não houve expressão em núcleo de NF-B-p65 nos tumores residuais. A expressão imunoistoquímica de HER-2 nos tumores primários foi de encontrada em 21,9% dos casos. Não houve expressão imunoistoquímica de HER-2 nos tumores residuais do colo uterino. A amplificação gênica de HER-2 nos tumores primários foi encontrada em 1 (3,1%) caso. Não houve expressão imunoistoquímica de IKK nos tumores primários ou residuais. As expressões imunoistoquímicas de HER-2, NF-B-p65 e NF-B-p50 não se correlacionaram com a resposta ao tratamento radioterápico pré-operatório. As expressões imunoistoquímicas positivas de NF-B-p65, NF-B-p50, IKK e HER-2 não se associaram a piores taxas de sobrevida livre de doença e sobrevida global. CONCLUSÕES: Nossos dados sugerem que as expressões imunoistoquímicas de NF-B e HER-2 não são capazes de predizer resposta à radioterapia e não estão relacionadas com pior prognóstico. O NF-B parece ser constitutivamente ativado no câncer do colo uterino / INTRODUCTION: The standard treatment of early cervical cancer is radical hysterectomy and concomitant radiation therapy and chemotherapy for advanced stages. After radical hysterectomy, adjuvant radiation therapy is indicated if risk factors are present. HER-2 is part of protein membrane family that has a critical role in cellular differentiation, proliferation and survival. The NF-B regulates apoptosis, cellular cycle, adhesion and cellular migration. NF-B is activated by IKK kinase. NF-B activation is related to resistance to radiotherapy and chemotherapy. The overexpression of HER-2 may activate the NF-B pathway through PI3K/Akt. Our aims were: a) analyze the immunohistochemical expression of HER-2, NF-B-p50, NF-B-p65 and IKK in patients with cervical cancer treated with radiation therapy followed by radical hysterectomy; b) analyze the HER-2 amplification gene with FISH; c) evaluate the immunohistochemical expression of HER-2, NF-B-p50, NF- B-p65 and IKK as a prognostic factor to recurrence and death. MATERIALS AND METHODS: A retrospective analysis was carries out on 32 patients with cervical cancer submitted to radical hysterectomy after neoadjuvant radiotherapy from January 1992 to June 2001. RESULTS: The median age was 45 years (22-67). One patient was stage IB2 (FIGO) and 31 IIB (96,9%). All patients received external beam radiotherapy and high dose vaginal brachytherapy. Sixteen (50%) patients had residual pathological disease after radical hysterectomy. Median follow-up time was 73.5 months and overall 5-year survival was 66.5%. Immunohistochemical cytoplasmic expression of NF-B-p65 e NF-B-p50 before radiotherapy was found in respectively 90.6% and 96.9% of cases. Immunohistochemical nuclear expression of NF-B-p65 and NF-B-p50 before radiotherapy was found in both 59.4% of cases. Immunohistochemical cytoplasmic expression of NF-B-p65 and NF-B-p50 in the residual tumors after radiotherapy was found in both 50% of cases. Immunohistochemical nuclear expression of NF-B-p50 in the residual tumors was found in 75% of cases. There was no nuclear expression of NF-B-p65 in the residual tumors. Immunohistochemical expression of HER-2 was found in 21.9% of cases. However, gene amplification was found in one case (3.1%). There was no expression of IKK in neither primary nor residual tumors. HER-2 and NF-B were not correlated to the risk of residual tumor after radiotherapy. Immunohistochemical expression of HER-2 and NF-B were not correlated to risk of recurrence or death. CONCLUSIONS: Our data suggest that NF-kB is constitutively activated in advanced cervical cancer. NF-kB and HER-2 may not predict response to radiotherapy and do not correlate to poor outcome

O câncer de mama corresponde a aproximadamente um quarto das neoplasias malignas em mulheres. A incidência do câncer de mama no Brasil é de cerca de 50.000 novos casos por ano, sendo considerado importante problema de saúde pública. HER2 e receptores hormonais (receptores de estrógeno e progesterona) são considerados os mais importantes marcadores prognósticos e preditivos em carcinoma de mama. A amplificação do gene HER2 ou a superexpressão da proteína HER2, que ocorre em cerca de 20 porcento dos carcinomas de mama, está associada a curso clínico mais agressivo e determina elegibilidade para terapia específica anti-HER2 com trastuzumabe. A terapia hormonal reduz em mais de 50 porcento o risco relativo de recorrência da doença em pacientes com tumores sensíveis a esse tratamento. Os testes de HER2 e receptores hormonais são partes essenciais da avaliação clínica das pacientes com carcinoma de mama; resultados precisos são fundamentais na identificação de pacientes que podem ser beneficiadas por terapias específicas. O presente estudo investigou a concordância nos resultados dos testes de HER2 e receptores hormonais determinados por imuno-histoquímica em 500 carcinomas invasivos de mama entre um laboratório referência e laboratórios locais de todas as regiões geográficas do Brasil. Os resultados demonstram baixa concordância geral (171/500 casos, 34,2 porcento) em relação aos resultados do teste de HER2 entre laboratórios locais e referência, o que pode estar relacionado ao baixo volume de testes de HER2 realizados, inexperiência com o sistema de escores de HER2 e/ou questões técnicas relacionadas à imuno-histoquímica nos laboratórios locais. A concordância nos resultados do teste de receptores de estrógeno e progesterona foi de 89,4 porcento (447/500 casos) e de 85,0 porcento (425/500 casos), respectivamente, entre laboratórios locais e referência. Padronização dos testes de HER2 e receptores hormonais com medidas de controle de qualidade rigorosas por laboratórios locais é fortemente recomendada para se evitar o tratamento inadequado de pacientes com câncer de mama / Breast cancer accounts for approximately one quarter of all cancers in females. The incidence of breast cancer in Brazil is about 50,000 new cases per year, and it is considered an important public health problem. HER2 and hormone receptors (estrogen and progesterone receptors) are considered the main prognostic and predictive markers for breast carcinoma. HER2 gene amplification or HER2 protein overexpression, detected in about 20 percent of breast carcinomas, predicts a more aggressive clinical course and determines eligibility for targeted therapy with trastuzumab. Hormonal therapy reduces the relative risk of recurrence by more than 50% in breast cancer patients with hormone-sensitive tumors. HER2 and hormone receptors testing has become an essential part of the clinical evaluation of all breast carcinoma patients, and accurate results are critical in identifying patients who may benefit from targeted therapy. The present study investigated the concordance in the results of HER2 and hormone receptors immunohistochemistry assays performed in 500 invasive breast carcinomas between a reference laboratory and local laboratories from all geographic regions of Brazil. Our results showed an overall poor concordance (171/500 cases, 34.2 percent) regarding HER2 results between local and reference laboratories, which may be related to the low-volume load of HER2 assays, inexperience with HER2 scoring system, and/or technical issues related to immunohistochemistry in local laboratories. The concordance of estrogen and progesterone receptors results was 89.4 percent (447/500 cases) and 85.0 percent (425/500 cases), respectively, between local and reference laboratories. Standardization of HER2 and hormone receptors testing with rigorous quality control measures by local laboratories is highly recommended in order to avoid erroneous treatment of breast cancer patients

Dans un premier temps, nous avons réalisé des revues systématiques de la littérature avec méta-analyses des données de survie. Ceci nous a conduits à sélectionner 4 marqueurs de mauvais pronostic pour la survie des CBNPC: le récepteur au facteur de croissance épidermique (EGF-R), un autre récepteur de cette famille (c-erbB-2) ainsi que deux autres facteurs potentiellement témoins de leur activité, Ki-67 (impliqué dans la prolifération) et le nombre des micro-vaisseaux (témoins de la néoangiogenèse). Dans une deuxième phase, nous avons étudié au laboratoire diverses questions sur des tumeurs bronchiques invasives. Premièrement, nous avons investigué le mécanisme de surexpression d’EGF-R et de c-erbB-2 et évalué si des anomalies génétiques pouvaient prédire cette surexpression, en recourant à des techniques d’immunohistochimie et de FISH. Ceci nous a permis d’observer que, si la majorité des CBNPC réséqués présentent des anomalies génétiques d’EGF-R et/ou de c-erbB-2, une amplification de ces gènes n’est présente que dans une minorité d’entre eux et n’est pas strictement corrélée à l’expression protéique. D’autre part, la survie de ces patients exprimant ou ayant une anomalie génique d’EGF-R et/ou c-erbB-2 est plus courte sans atteindre le seuil de signification statistique. Deuxièmement, nous avons recherché sur des tumeurs opérées d’éventuels liens entre les expressions d’EGF-R, de c-erbB-2 et de Ki-67. Aucune corrélation n’a été mise en évidence entre l’expression de ces 3 facteurs. Par contre, chez ces patients, l’expression de Ki-67 dans la tumeur s’est avérée être un facteur de mauvais pronostic pour la survie. Troisièmement, nous avons voulu savoir si un de ces marqueurs (EGF-R) présentait une valeur pronostique dans un groupe plus restreint de tumeurs plus avancées, les CBNPC de stade III. Pour mener cette recherche sur des biopsies, nous avons d’abord démontré que l’évaluation des marqueurs biologiques (EGF-R, c-erbB-2 et Ki-67) sur biopsie ne différait pas de celle réalisée sur des tumeurs réséquées. Comme les résultats étaient équivalents, nous avons pu étudier EGF-R sur les biopsies de CBNPC au stade III et montrer qu’EGF-R n’était pas un facteur pronostique pour la survie dans ce groupe assez homogène de tumeurs avancées. Dans la dernière phase, nous avons étudié des lésions représentatives des différents stades prénéoplasiques et néoplasiques précoces radiooccultes. Ces lésions ont été prélevées lors d’examens endoscopiques de photodétection. EGF-R, c-erbB-2, Ki-67 et le nombre des micro-vaisseaux ont été étudiés par immunohistochimie dans ces différents stades de lésions prénéoplasiques et néoplasiques précoces. Nous avons observé qu’EGF-R et Ki-67 sont statistiquement plus exprimés dans les dysplasies sévères et les carcinomes in que dans les dysplasies légères suggérant que, au moins pour ces 2 marqueurs, les dysplasies sévères se rapprochent plus des carcinomes in situ que des dysplasies légères. Alors que l’expression d’EGF-R est présente dès le stade de dysplasie sévère, une augmentation du nombre des micro-vaisseaux n’est présente qu’au stade de tumeurs micro-invasives. C-erbB-2 n’est quant à lui pas exprimé dans ces lésions bronchiques prénéoplasiques et néoplasiques précoces. En conclusion, les facteurs biologiques, EGF-R, c-erbB-2 et Ki-67 et le nombre des micro-vaisseaux s’avèrent des facteurs de mauvais pronostic dans le CBNPC. La surexpression d’EGF-R et de c-erbB-2 dans les cancers réséqués résulte très rarement d’une amplification génique et nous n’avons pas trouvé dans ces tumeurs de corrélation entre l’expression des marqueurs moléculaires étudiés. Dans les tumeurs plus avancées de stade III, EGF-R n’est pas un facteur discriminant pour le pronostic. Les anomalies de certains de ces marqueurs (EGF-R et Ki-67) apparaissent précocement, dès les stades prénéoplasiques, avec un seuil se situant entre les lésions bronchiques de bas et de haut grades. La néoangiogénèse, évaluée par le nombre des micro-vaisseaux, s’observe à partir des cancers micro-invasifs tandis que c-erbB-2 n’apparaît qu’au stade invasif. Dans la séquence d’apparition des anomalies génétiques conduisant au cancer invasif, l’atteinte d’EGF-R précède la néoangiogénèse.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Objetivo: Evaluar supervivencia y factores asociados en pacientes con CPCNP con la mutación del gen EGFR tratados con ITK en un Hospital de referencia peruano.Métodos: Se realizó un estudio observacional analítico de tipo cohorte retrospectivo durante 2009-2015. Las variables categóricas se presentaron como frecuencias y porcentajes. Se presentó la curva de Kaplan-Meier. Para el análisis bivariado, se analizó la asociación entre variables independientes y sobrevida utilizando el log Rank Test. Para el análisis multivariado se utilizó el método de riesgos proporcionales de Cox. Resultados: Se incluyeron 72 pacientes, seguidos durante un total de 1144 meses. Predominó género femenino (61.11%), pacientes no fumadores (62.50%), subtipo histológico adenocarcinoma (76.38%). El tipo de mutación del gen EGFR más frecuente fue la deleción del exón 19 (65.27%). La historia de tabaquismo fue del 37.5%. La mayoría de los pacientes se presentaron con comorbilidades (77.78%) siendo hipertensión arterial la más frecuente. Casi la totalidad de los pacientes se encontró en estadio IV. Fallecieron 65 (90.28%) casos. Se estimó que la mediana de sobrevida fue de 9.3 meses IC=95%(7.01-16.93). Al comparar las curvas de sobrevida (Long Rank test) se encontró que tipo histológico (p=0.01), lugar de mutación (p=0.06), hemoglobina (p=0.01) y edad (p=0.01) de los pacientes fueron significativas para la supervivencia global. En el análisis multivariado las variables asociadas significativamente fueron edad (HR=1.02, IC=1-1.04, p=0.009) y hemoglobina (HR=0.70, IC=0.55-0.89, p=0.003). Conclusión: La mediana de sobrevida global de los pacientes con mutación del gen EGFR con CPCNP tratados con ITK fue de 9,3 meses. Se encontró que una menor edad y una mayor cifra de hemoglobina fueron los factores asociados a una mayor sobrevida. / Objective: Evaluate the survival and prognostic factors in EGFR mutation non-small cell lung cancer (NSCLC) patients treated with tyrosine inhibitors (TKI) in a Peruvian reference hospital. Methods: Retrospective cohort analytical observational study was conducted in NSCLC patients from 2009-2015. Kaplan-Meier curve was presented. For the bivariate analysis, the association between independent variables and survival is analyzed using the Long-Rank test. For the multivariate analysis, the Cox proportional hazards method is used to calculate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) using time-to-event outcomes. Results: Were included 72 patients, following for a total of 1144 months. Predominantly female gender (61.11%), never smoked patients (62.50%), histological adenocarcinoma subtype (76.38%). The most frequent EGFR mutation was the deletion of exon 19 (65.27%). The history of smoking was 37.5%. The majority of patients present with comorbidities (77.78%), hypertension being the most frequent. Almost all patients were found in stage IV. 65 (90.28%) cases died. It was estimated that the median survival was 9.3 months CI = 95% (7.01-16.93). When comparing the survival curves using Long Range Test, it was found that histological type (p = 0.01), place of mutation (p = 0.06), hemoglobin (p = 0.01) and age (p = 0.01) were significant for overall survival. In the multivariate analysis significant characteristicsthe were age (HR = 1.02, CI = 1-1.04, p = 0.009) and hemoglobin (HR = 0.70, CI = 0.55-0.89, p = 0.003). Conclusion: The median overall survival of positive EGFR mutation NSCLC patients treated with TKI was 9.3 months. An association was found between a younger age and an a higher hemoglobin level with a longer survival. / Tesis

A incidência de adenocarcinoma de esôfago e cárdia tem aumentado nas últimas décadas por razões ainda não conhecidas. São doenças da civilização ocidental. A incidência de adenocarcinoma de esôfago e carcinoma de cárdia ultrapassou a de carcinoma epidermóide de esôfago. O desenvolvimento da biologia molecular e descoberta de oncogenes e genes supressores de tumores permitiu novos achados e melhor entendimento das características moleculares dos carcinomas de esôfago e cárdia. Novos genes envolvidos em ciclo celular, apoptose e reparo de DNA são agora alvo importante de estudos da patogênese destes tumores. HER-2/neu é um oncogene expresso in diversas neoplasias e relacionado à pior prognóstico. P53 é igualmente importante estando mutado em 50%-70% das neoplasias sólidas com implicações clínicas para muitos tumores. Este trabalho determina a frequência de p53 e HER-2/neu através de imunohistoquímica utilizando anticorpos policlonais e monoclonais DAKO anti-HER-2/neu e p53 respectivamente. Foram selecionados 22 casos de adenocarcinoma de esôfago e carcinoma de cárdia do departamento de cirurgia. HER-2/neu foi positivo em 47.7% dos casos, média entre dois observadores. P53 foi positivo em 36.6% dos casos. A correlação entre os escores de HER-2/neu e p53 foi estabelecida usando o coeficiente de correlação de Spearman que mostrou um resultado negativo –0.27 para o primeiro observador que não foi significante. Para o segundo observador, a correlação foi a mesma -0.27 e não significante, mostrando que o aumento na expressão de HER-2/neu não está relacionada com aumento de expressão de p53. Nós concluímos que a expressão de HER-2/neu neste grupo de neoplasias, necessita de investigações futuras e que mesmo estando alterado com muitos outros oncogenes em outros trabalhos, p53 não está correlacionado com aumento de expressão de HER-2/neu nesta série de casos.

Les proteines ErbBjHER appartiennent a la famille des recepteurs a activite tyrosine kinase (RrK). Ces recepteurs participent a un reseau complexe d'jnteractions a la surface de la cellule et controlent la proliferation et la differenciation cellulaire. Cette famille de 4 membres (ErbBljEGFR, ErbB2, ErbB3, ErbB4) forme des homodimeres etjou des heterodimeres apres fixation du ligand. La deregulation de ce reseau d'interactions est associee a de nombreux cancers humains.<br />Le domaine tr~smembranaire joue un role dans la fonction de ces recepteurs et l'implication des motifs de type GxxxG dans les processus d'association suscite un interet particulier. Des etudes experimentales montrent une correlation entre la hierarchie des interactions des recepteurs entiers et celIe des domaines transmembranaires.<br />Une methode theorique de recherche de modeles d'association des heterodimeres a ete develoHpee permettant de quantifier les interactions entre les domaines membranaires et de definir Ie role des motifs dans l'association. Des simulations de dynamique moleculaire effectuees sur l'ensemble des modeles montrent une preference d'association gauche des helices. Les petits residus appartenant aux motifs de dimerisation sont presents a l'interface des deux helices. Nos etudes montrent que les domaines transmembranaires participent a la specificite et a la selectivite des recepteurs dans les processus de dimerisation.

Astrocytic tumors are the most common malignancies of the central nervous system, accounting for more than 60% of all primary brain tumors. The prognosis for high grade astrocytoma patients is dismal and there is no curative treatment, today. A molecular hallmark of astrocytic tumors is dysregulated receptor tyrosine kinase signaling, especially of the epidermal growth factor receptor (EGFR, ErbB1). The aim of the present thesis was to identify endogenous human proteins that downregulate the function of the ErbB1 receptor. We identified a human gene family, the leucine-rich repeats and immunoglobulin-like domains family (LRIG), consisting of LRIG1, LRIG2 and LRIG3, which might fulfill this criterion. Two candidates were identified, LRIG1 and LRIG2, which genes were localized to regions frequently deleted in human cancers, chromosome bands 3p14 and 1p13, respectively. LRIG1 and LRIG2 mRNA were expressed in all tissues analyzed, with high expression in brain and other organs. The LRIG mRNA were predicted to encode integral membrane proteins. Antibodies against LRIG1 and LRIG2 were developed and the protein expression was analyzed. LRIG1 was found to have an apparent molecular weight of 143 kDa and was expressed in most tissues with high expression in glandular tissues of the breast and prostate, and the peptic cells of the stomach. LRIG2 was slightly smaller and had an apparent molecular weight of 132 kDa. The LRIG proteins were localized to the cell surface and to perinuclear structures, where LRIG1 co-localized with the trans-Golgi network and early endosomes. LRIG1 was found to restrict growth factor signaling by enhancing receptor ubiquitylation and degradation. We showed that LRIG1 interacted with all four members of the ErbB family and induced their downregulation. The interaction with ErbB1 involved both the LRR-domains and the Ig-like domains of LRIG1. LRIG1 enhanced receptor degradation by recruiting the E3 ubiquitin ligase c-Cbl to the LRIG1-ErbB1 complex. LRIG1, LRIG2, and LRIG3 were expressed in glioma cell lines and tumor tissues. The LRIG expression was analyzed in 404 astrocytic tumor samples. We found that perinuclear LRIG protein expression correlated with increased survival of patients with astrocytic tumors. Especially perinuclear LRIG3 showed strong correlations with patient survival and tumor cell proliferation index. In summary, this thesis contains the discovery and characterization of human LRIG1 and LRIG2. LRIG1 was found to interact with ErbB receptors and downregulate their function. In a clinical material, expression of LRIG proteins correlated with survival in patients with astrocytic tumors.

The ErbB family of receptors are key regulators of growth, differentiation, migration and survival of epithelial cells. CI-1033 is an irreversible pan-ErbB tyrosine kinase inhibitor that has the ability to inhibit EGFR function but has shown limited therapeutic efficacy. Lovastatin targets the activity of HMG-CoA reductase, the rate-limiting step in the mevalonate pathway. In this study, the ability of lovastatin to potentiate the cytotoxic effects of CI-1033 was evaluated. The combination of lovastatin and CI-1033 exhibited some cooperative cytotoxic activity in a squamous cell carcinoma–derived cell line. This combination resulted in enhanced cell death by induction of a potent apoptotic response. Furthermore, this drug combination inhibited EGF-induced EGFR autophosphorylation and activation of the downstream signaling effectors, ERK and AKT. These findings suggest that combining lovastatin and tyrosine kinase inhibitors may represent a novel combinational therapeutic approach in squamous cell carcinoma of the head and neck.