Advanced HNSCC Research Articles

EP-1085: Comparative study of outcomes and toxicities in conventional 2DRT vs IMRT in locally advanced HNSCC

EP-1085: Comparative study of outcomes and toxicities in conventional 2DRT vs IMRT in locally advanced HNSCC

PO-059: Efficacy and safety of modified-increased FEP regimen and chemo-radiation for locally advanced HNSCC

PO-059: Efficacy and safety of modified-increased FEP regimen and chemo-radiation for locally advanced HNSCC

PITX2 and PANCR DNA methylation predicts overall survival in patients with head and neck squamous cell carcinoma.

BackgroundSquamous cell carcinoma of the head and neck region (HNSCC) is a common malignant disease accompanied by a high risk of local or distant recurrence after curative-intent treatment. Biomarkers that allow for the prediction of disease outcome can guide clinicians with respect to treatment and surveillance strategies. Here, the methylation status of PITX2 and an adjacent lncRNA (PANCR) were evaluated for their ability to predict overall survival in HNSCC patients.ResultsPITX2 hypermethylation was associated with a better overall survival (hazard ratio, HR = 0.51, 95%CI: 0.35-0.74, p<0.001), while PANCR hypermethylation was significantly associated with an increased risk of death (HR = 1.64, 95%CI: 1.12-2.39, p=0.010).MethodsQuantitative, methylation-specific real-time PCR assays for PITX2 and PANCR were employed to measure bisulfite-converted DNA from formalin-fixed, paraffin-embedded (FFPE) tissues in a cohort of 399 patients with localized or locally advanced HNSCC who received curative-intent treatment (surgery with optional adjuvant radiochemotherapy or definite radiochemotherapy).ConclusionsPITX2 and PANCR methylation status were shown to be independent predictors for overall survival in HNSCC patients. Tissue-based methylation testing could therefore potentially be employed to identify patients with a high risk for death who might benefit from a more radical or alternative treatment.

983P - An advanced tumor shape radiomic signature predicts recurrence of locally advanced (LA) HNSCC patients (pts)

983P - An advanced tumor shape radiomic signature predicts recurrence of locally advanced (LA) HNSCC patients (pts)

Induction Chemotherapy Followed by Concurrent Chemoradiotherapy versus Radiotherapy Alone in Locally Advanced HNSCC – An Experience from Medical College in West Bengal, India

&lt;em&gt;Locally advanced Head and neck cancers (LAHNSCCs) are emerging as an important public health issue in India. Our study was designed to provide NACT to LAHNSCC patients followed by comparison between chemoradiation versus only radiation in rural medical college.&lt;/em&gt;

Abstract 3356: Characterization and enrichment of head and neck cancer stem cells suggests differences between HPV+ and HPV- subtypes of HNSCC cells

Abstract Head and neck squamous cell carcinomas (HNSCC) are the sixth most prevalent type of malignancy worldwide. Despite recent advances in multidisciplinary treatments, the overall survival and quality of life of patients with advanced HNSCC have not improved considerably over the past decade. Recent reports have demonstrated that tumors contain a small subpopulation of cells called cancer stem-like cells (CSCs), which are responsible for tumor maintenance and metastasis. CSCs have the ability to self-renew and are responsible for tumorigenesis, progression, metastasis, and relapse after treatment. Recent studies demonstrate that even established HNSCC cell lines contain a definite sub-population of CSC providing us with the opportunity to discerning their roles in progression, treatment, and relapse of the disease. In vitro Sphere Forming Assays (using ultra-low attachment plate and serum free media) were employed as the key method of CSC enrichment. qPCR analyses, aldehyde dehydrogenase (ALDH) activity, Side Population Phenotype assay (SPP) were used to confirm the results of the primary analyses. To confirm an in vivo CSC phenotype, xenograft tumor formation, through subcutaneous injection in immunocompromised mice was done. In vitro sphere forming assay followed by subsequent passaging of the sphere enriched cells (SECs) have successfully demonstrated the existence and enrichment of a CSC sub-population in HNSCC cell lines. Findings suggest a differential existence of CSCs related to the HPV status of the cell. ALDH assay and SPP assay confirmed the results of sphere formation. qPCR analyses of the SECs have confirmed enrichment in several stemness marker genes (Oct-4, Sox2, Nanog, Bmi-1, cMyc, KLF4, Beta catenin etc.), also following the identical differential pattern. Various EMT markers genes (Vimentin, Fibronectin, E-cadherin, N-cadherin, Snail, Slug, Twist, ZO-1 etc.) were also assessed, portraying a significant level of expression in CSC populations. SECs subcutaneously injected in immunocompromised mice formed tumors with as few as 50 cells. We have demonstrated that a definite subpopulation of CSCs exists in HNSCC cell lines. Significant differences were seen between the HPV+ and HPV- subtypes. Analyses of EMT marker genes and other molecular pathways in CSC confirm the differences between HPV+ and HPV- cells too following the similar pattern. In vivo tumor xenograft formation establishes the heightened tumorigenicity of CSCs/SECs. Citation Format: Anirban Chatterjee, Kwangok Nickel, Randall J. Kimple. Characterization and enrichment of head and neck cancer stem cells suggests differences between HPV+ and HPV- subtypes of HNSCC cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3356.

A radiomic signature based on advanced tumor shape parameters (Spiculated-ness) to predict the outcome of locally advanced (LA) HNSCC patients.

11571Background: Tumor invasion patterns are known to be associated with HNSCC pts outcome. Radiomics is a rapidly-emerging field involving the extraction of quantitative imaging features from stan...

Induction Chemotherapy Followed By Concurrent Chemoradiotherapy Versus Radiotherapy Alone In Locally Advanced HNSCC – An Experience From Medical College In West Bengal, India

&lt;p&gt;&lt;strong&gt;Introduction:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Locally advanced Head and neck cancers (LAHNSCCs) are emerging as an important public health issue in India. Our study was designed to provide NACT to LAHNSCC patients followed by comparison between chemoradiation versus only radiation in rural medical college.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Material and Method: &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Histopathologically proven non-metastatic LAHNSCC were randomized into 2 arms. Patients in both arms initially received 3 cycles of NACT (inj Paclitaxel 175mg/m2 and inj Carboplation AUC 6, i.v, q 21 days). Thereafter they received definitive treatment accordingly: arm A (control arm) received conventionally fractionated radiotherapy (CFRT), 70 Gy in 35 # and in arm B (study arm) received conventionally fractionated radiotherapy (CFRT), 70 Gy in 35 # with concomitant 3 weekly cisplatin 100mg/m2. A RECIST v1.0 criterion was used for response assessment and toxicities evaluated by RTOG Acute and late Morbidity scorings.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Between July 2013 to December 2015, 140 patients were randomized into arms. Laryngeal and hypopharyngeal subsites together accounted for 36.4% patients. 70% of patients were in AJCC TNM 7th edition stage IV. 87.8% of patients completed the planned 3 cycles of NACT. Response assessment using RECIST v1.0 criteria after NACT were comparable in both arms with CR in 25% patients and PR in another 60% patients, p value 0.963. After completion of full treatment, 68.57% (48/70) patients in concurrent arm had CR against 55.72% patients (39/70) in only radiation arm, p value 0.241. At the end of study, 38 patients in arm A and 46 patients in arm B were eligible for response assessment. 24 patients (63.2%) in arm A were in complete response against 32 patients (69.6%) in concurrent chemoradiation arm, p value 0.535. Gastrointestinal and mucositis grade 3 toxicities were significantly increased in concomitant chemoradiation arm.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion: &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Our study failed to show any statistical significant improvement in CR in favour of CTRT arm in our subset of patients. Yet definitive conclusion regarding use of only radiation cannot be made for LAHNSCC especially when combined with induction chemotherapy.&lt;/p&gt;

OC-0262: Comparison of machine-learning methods for predictive radiomic models in locally advanced HNSCC

OC-0262: Comparison of machine-learning methods for predictive radiomic models in locally advanced HNSCC

Up-regulation of HB-EGF by the COX-2/PGE2 signaling associates with the cisplatin resistance and tumor recurrence of advanced HNSCC

When treating advanced HNSCC, a cisplatin-based systemic regimen benefit patient survival. However, chemoresistance will greatly reduce the effectiveness of this approach. The identification of molecules that contribute to cisplatin resistance may potentially improve the survival. Both HB-EGF and COX-2 have been reported to increase cisplatin-resistance. Here, we have focused on the regulation of HB-EGF/COX-2 and their roles in cisplatin resistance. IHC staining was used to measure the expression levels of HB-EGF and COX-2 on the tissue microarray from 43 tissue samples of patients with advanced HNSCC. siRNA, western blot and qRT-PCR were used to dissect the regulation between EGF, Akt, COX-2, PGE2, and cisplatin sensitivity. The correlation between HB-EGF, COX2 and HNSCC progression was analyzed by the receiver operating characteristic (ROC) curve and Kaplan-Meier disease free survival. Patients of advanced HNSCC patients with increased HB-EGF and COX-2 expression have higher tumor recurrent rates that was related to cisplatin resistance. The resistance was mediated via an increased expression of HB-EGF and COX-2. The activation of Akt by either EGF or areca nut extract were able to upregulate COX-2, which would increase the expression of HB-EGF in a PGE2 dependent manner. Inhibition and knockdown of COX-2 resulted in a decrease in HB-EGF. In the tissue samples from HNSCC patients, there was a significant positive correlation between the expression of COX-2 and HB-EGF. Our results suggested that COX-2 and HB-EGF are important in development of HNSCC cisplatin resistance. These findings may help the development of new strategies for overcoming cisplatin resistance.

Predictive and prognostic value of PET/CT imaging post-chemoradiotherapy and clinical decision-making consequences in locally advanced head & neck squamous cell carcinoma: a retrospective study.

BackgroundThe accuracy of 18F-fluorodeoxygluocose positron emission tomography/computed tomography (PET/CT) in predicting immediate failure after radical chemoradiotherapy (CRT) for HNSCC is poorly characterized at present. The purpose of this study was to examine PET/CT as a predictive and prognostic gauge of immediate failure after CRT and determine the impact of these studies on clinical decision making in terms of salvage surgery.MethodsMedical records of 78 consecutive patients receiving radical CRT for locally advanced HNSCC were reviewed, analyzing PET/CTs done before and 3 months after CRT. Immediate failure was defined as residual disease or locoregional and/or systemic relapse within 6 months after CRT.ResultsMaximum standard uptake value (SUV) of post CRT PET/CT (postSUVmax) was found optimal for predicting immediate failure at a cutpoint of 4.4. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were 90.0 %, 83.8 %, 98.3 %, and 45.0 %, respectively. Of 78 patients studied, postSUVmax ≥4.4 prevailed in 20 (25.6 %), with postSUVmax <4.4 in 58 (74.4 %). At postSUVmax ≥4.4 (vs. postSUVmax <4.4) OS was poorer by comparison (3-year OS: 56.9 vs. 87.7 %; P = 0.005), as was progression-free survival (3-year PFS: 42.9 vs. 81.1 %; P < 0.001). At postSUVmax ≥4.4, OS with and without immediate salvage surgery did not differ significantly (3-year OS: 60.0 vs. 55.6 %; Log-rank P = 0.913).ConclusionPost CRT PET/CT imaging has prognostic value in terms of OS and PFS and is useful in predicting immediate therapeutic failure, given its high NPV. However, OS was not significantly altered by early salvage surgery done on the basis of post CRT PET/CT findings.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2147-y) contains supplementary material, which is available to authorized users.

Induction chemotherapy followed by concurrent radio-chemotherapy versus concurrent radio-chemotherapy alone as treatment of locally advanced squamous cell carcinoma of the head and neck (HNSCC): A meta-analysis of randomized trials

BackgroundInduction chemotherapy with docetaxel, cisplatin and 5 FU (TPF) before radiotherapy (RT) or radio-chemotherapy (RT-CHX) has been shown to improve overall survival (OS) compared to induction chemotherapy with cisplatin and 5 FU in locally advanced squamous cell carcinoma of the head and neck (HNSCC). Whether TPF induction before RT-CHX improves clinical outcome in comparison with RT-CHX alone is still a matter of debate. Recently, the results of 5 randomized trials addressing this question have become available. MethodsIn the 5 trials of interest, in total 1022 patients with locally advanced HNSCC were randomly assigned to receive either TPF induction CHX followed by concurrent RT-CHX or concurrent RT-CHX alone. Platin or taxane based CHX was used during RT. 51.3% of the patients had oropharyngeal, 7.3% hypoharyngeal, 18.7% laryngeal, 19.4% oral cavity and 3.5% had other HNSCC. Published hazard ratios and hazard ratios extracted from available survival curves for OS and progression free survival (PFS) were basis of the meta-analysis. Meta-analysis of the effect sizes on OS and PFS was performed using a random effects model based on parameter estimates of log hazard ratios in Cox models and their standard errors. ResultsAdditional induction CHX with TPF before RT-CHX did neither result in a significant improvement of OS (Hazard Ratio: 1.010, 95% confidence limits (CL) 0.84–1.21, p=0.92), nor in a statistically significant benefit of PFS (Hazard Ratio: 0.91, 95% CL 0.75–1.1, p=0.32). ConclusionAdditional induction CHX with TPF before RT-CHX does not improve OS and PFS in locally advanced HNSCC compared to definite RT-CHX.

A phase 2 randomized study to compare short course palliative radiotherapy with short course concurrent palliative chemotherapy plus radiotherapy in advanced and unresectable head and neck cancer

BackgroundTreatment of unresectable HNSCC is not well defined and has a poor outcome. This study has been designed to address the unmet needs of such groups of patients with primary end points of (a) proportion of patients eligible for radical treatment in each arm (b) loco-regional disease control at 6months between two arms. Materials and methodsLocally advanced and unresectable HNSCC patients (except Nasopharynx and Larynx) unfit for radical treatment were randomized to arm A [short course RT alone (4Gy/#/day for 5days)] or arm B [RT as arm A+concurrent cisplatin at 6mg/m2/day IV bolus for 5days]. Those with at least PR were taken for further RT to complete biological equivalent dose of 70Gy, in both the arms. In arm B, concurrent CDDP at a dose of 40mg/m2/week was administered. Results114 patients (57 in each arm) were randomized but 111 were analyzable. 15 (27.27%) patients in arm A and 28 (50%) patients in arm B had ⩾PR (p=0.01) however patients taken for FRT were 14 (25.45%) and 26 (46.42%) in arms A and B respectively (p=0.02). Locoregional control i.e. (CR+PR) at 6months was 16.36% in arm A versus 32.14% in arm B (p=0.15). Median PFS (arm A – 3.2months, arm B – 6.2months; p=0.02) and OS (arm A – 5.9months, arm B – 10.1months; p=0.03) was significantly more in arm B. There was relative improvement in quality of life for most parameters in arm B. ConclusionConcurrent low dose CTRT can be an effective treatment modality in advanced and incurable HNSCC. However, a larger phase III trial is required.

Abstract 1036: A muscle specific protein “myoferlin” modulates IL-6/STAT3 signaling by chaperoning activated STAT3 to nucleus

Abstract Head and neck squamous cell carcinoma (HNSCC) is the sixth most frequent cancer worldwide and five-year survival rates (&amp;lt;50%) are among the lowest of the major cancers. Although advancements in the anti-cancer treatments including surgery, radiation and chemotherapy have increased the local control of HNSCC, the overall survival rates have not improved significantly over the last three decades. This poor outcome becomes even worse (20%, 5-year survival rate) for advanced HNSCC patients that have become resistant to standard chemoradiation treatment. Therefore, there is an urgent need to identify new therapeutic targets so that novel treatment regimen(s) can be developed to improve the therapeutic efficacy while minimizing the toxicity. Recently, we made a provocative and novel discovery in our laboratory that a muscle-specific protein, myoferlin, is markedly upregulated in head and neck cancer cells. Myoferlin is a member of ferlin family of membrane proteins and most of the studies related to myoferlin's biological and molecular function(s) were carried out on muscle cells, as it was assumed that myoferlin is predominantly present only in the muscle cells. Recent studies have shown that myoferlin is also expressed in other cell types including endothelial cells and cancer cells. In our study, we observed that in addition to being expressed in tumor cells, myoferlin levels were further elevated in highly chemoresistant cells. Furthermore, myoferlin expression was also significantly higher in patients with HPV-negative tumors that show markedly poor clinical outcome and often develop resistance to chemotherapy as compared to HPV-positive tumors that normally respond better to traditional chemotherapy. Knockdown of myoferlin in head and neck cancer cells by siRNA significantly reversed chemoresistance and markedly decreased ALDH positive cancer stem cell population. These results suggest that myoferlin might be a contributing factor in the aggressive and metastatic phenotype in HNSCC. Our mechanistic studies demonstrate a novel role for myoferlin in cancer cells. Our results showed that myoferlin is bound to EHD2 protein in the resting cancer cell. Treatment of these cancer cells with IL-6 induced STAT3 phosphorylation, which led to myoferlin dissociation from EHD2 and binding to phosphorylated STAT3. Interestingly, myoferlin knock-down did not affect STAT3 phosphorylation, but completely blocked STAT3 translocation to nucleus and expression of its target proteins including Snail and Nanog. Based on these results, we have proposed a novel model for the role of myoferlin in chaperoning phosphorylated proteins to the nucleus. Taken together, our results from this study provide a novel oncogenic function of a muscle-specific protein, myoferlin, which may lead to the development of innovative therapeutic strategies to target HNSCC. Citation Format: Arti Yadav, Bhavna Kumar, Theodoros N. Teknos, Pawan Kumar. A muscle specific protein “myoferlin” modulates IL-6/STAT3 signaling by chaperoning activated STAT3 to nucleus. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1036. doi:10.1158/1538-7445.AM2015-1036

Molecular targeting in combination with platinum-based chemoradiotherapy in head and neck cancer treatment.

Significant evidence exists supporting the use of platinum-based chemoradiotherapy (CRT) as a primary curative approach in locoregionally advanced head and neck cancer (HNSCC). Despite these aggressive protocols, 70% of patients die within 5 years because of locoregional recurrence or distant metastasis. To increase the response and survival of patients with HNSCC, CRT has been combined with molecular agents targeting distinct kinases. This study was performed using a systematic literature review. The effect of targeted therapy on patient survival in the context of CRT remains controversial, with toxicities tending to be more severe but still acceptable. Supplementing CRT with target therapeutics might only improve survival in some patients with locally advanced HNSCC. Therefore, future studies must address the underlying biological mechanisms that can have an impact on treatment response. Such knowledge is essential in order to facilitate the effective and personalized treatment of patients with locally advanced HNSCC by combining CRT and targeted therapy. © 2015 Wiley Periodicals, Inc. Head Neck 38: E2173-E2181, 2016.

Prognostic impact of C-reactive protein in primary, advanced and recurrence HNSCC.

e17060 Background: The purpose of our study was to investigate the significant impact of C-reactive protein (CRP) level as a prognostic factor of relapse of HNSCC and as a predictive marker of chem...

2 Effects of sorafenib treatment on HNSCC cells in combination with cisplatin based-chemoradiation

Background To improve the outcome of patients with squamous cell carcinoma of the head and neck (HNSCC) and reduce the side effects of radiochemotherapy, the combination of target therapeutics with established chemoradiation protocols is under investigation. Sorafenib, a multikinase inhibitor, has a cytotoxic and antiproliferative effect as a monotherapy and acts as a radiosensitizer of HNSCC cell lines. As cisplatinbased chemoradiation is the standard treatment for locally advanced HNSCC, the aim of this study was to identify the influence of sorafenib on cisplatin + radiation treatment in HNSCC cell lines and to determine the effects on normal cells, to assess potential dose limiting toxicities. Material and methods Two different HNSCC cell lines (UT-SCC42A and UT-SCC42B) were treated by combination of Sorafenib (10 μ M; Nexavar®, Bayer) and Cisplatin (1–10 μ M) with/without irradiation (2–6 Gy). Cell number was assessed to determine the proliferation rate and colony formation assay was performed for estimation of cell survival. Fibroblasts (F180) were treated similarly to evaluate the cytotoxicity in non-tumor cells. Results Cisplatin has a dose-dependent antiproliferative effect in both cell lines. The growth inhibitory effect is clearly increased by addition of Sorafenib in a dose of 5 μ mol/l, according to a synergistic effect to cisplatin. In colony formation assay Cisplatin and Sorafenib have a dose-dependent cytotoxic effect in both cell lines. The combined treatment shows a sensitization of UT-SCC42A & 42B cells by Sorafenib against Cisplatin treatment, according to a chemosensitization. In both tested cell lines we observe a radiosensitization by sorafenib (10 μ mol/l) in presence of cisplatin (all tested doses), in contrast to only a minor radiosensitizing effect on HNSCC cells by Cisplatin alone. Fibroblasts (F180) were not affected by Sorafenib in terms of cell inactivation investigated in the colony formation assay. Conclusion Sorafenib acts as a radio- and chemosensitizer in two tested cell HNSCC cell lines and has no cytotoxic effect on normal fibroblasts. Therefore the combination of sorafenib with cisplatin-based chemoradiation may improve the efficacy of HNSCC treatment in terms of survival outcome and side effects.

OC-007: Is accelerated radiotherapy alone equivalent to chemo-radiation in patients with moderate advanced HNSCC?

OC-007: Is accelerated radiotherapy alone equivalent to chemo-radiation in patients with moderate advanced HNSCC?

A survey on pulmonary screening practices among otolaryngology-head &amp; neck surgeons across Canada in the post treatment surveillance of head and neck squamous cell carcinoma

BackgroundPost treatment lung screening for head and neck cancer patients primarily focuses on the distant metastasis and a high rate of second primary can also be expected. The best screening tool and timing for this purpose is controversial. We sought out to assess the current practice and beliefs among Canadian Head and Neck Surgeons.MethodsAfter Ethical Board approval, a nationwide survey was conducted through the Canadian Society of Otolaryngology (CSO) among head and neck surgeons regarding their practices for pulmonary screening in HNSCC patients.ResultsOur CSO survey among Otolaryngology-head and neck surgeons showed that 26 out of 32 respondents perform routine lung screen, out of which 23 (88%) feel that chest radiography should be preferred. The majority of respondents felt that lung screening could impact beneficially on mortality. For symptomatic patients, low-dose spiral CT was the preferred modality (48%), followed by PET/CT scan (14%) and sputum cytology (14%). In high-risk asymptomatic patients (current smoker, radiation exposure, family history and advanced HNSCC), 31% of respondents performed a CXR. The same percentage performed a low dose CT, while 19% relied on PET scan. A further 19% of respondents did not perform any screening in high-risk patients. Most respondents (77%) had more than 10 years practice since graduation from medical school and came from the provinces of Quebec, Ontario and Alberta.ConclusionChest radiography remains the preferred modality for lung screening and was believed to be impacting beneficially on lung mortality. The recent literature does not seem to be in agreement with those beliefs. Further studies to establish which modality is best and concurrent nation-wide education are warranted.

Abstract 1876: Combination of PI3KCA targeting with irradiation: A preclinical study on head and neck cancer cell lines

Abstract Purpose In complement to anti-EGFR therapy, the targeting of PI3KCA/AKT/mTOR signalling pathway is of particular interest in the management of HNSCC. Its activation is recognized as an important mechanism in tumor progression and resistance to EGFR inhibitors. Of importance, PI3KCA inhibitors have shown their ability to selectively inhibit the PI3KCA/AKT signalling and to enhance the effects of conventional cytotoxic agents. Therefore, it would be particularly interesting to assess the effects of PI3KCA inhibition combined with anti-EGFR monoclonal antibody (cetuximab) and/or irradiation (RT). Experimental procedures We identified two HNSCC cell lines (Cal 33, PIK3CA H1047R mutated and Cal 27, wild type) and examined the effects of the combination of BKM120 (specific inhibitor of PI3KCA), cetuximab and RT. Experimental conditions were: BKM120, cetuximab, RT alone; sequence 1 (BKM120 followed by cetuximab), sequence 2 (cetuximab followed by BKM120) and combination (BKM120 + cetuximab together) with/without RT given ahead of all treatments. Drugs were administered at their IC50. Cell survival was assessed by MTT test. Combination effects were analyzed by the Combination Index (CI) and Compusyn software. Biochemical factors were examined for the impact on proliferation, apoptosis (caspases), DNA repair (ERCC1, XRCC1, DNA-PK, ATM) and PI3KCA/AKT/mTOR pathway p-P70/S6k, p-Akt/Akt, PTEN). Gene expression was determined by real time-PCR and protein expression by western blot. Results We evidenced sequence 2 as the best combined treatment in inhibiting cell proliferation in both cell lines (ΔIC50 = - 7.91*10-6 M in Cal 7 and ΔIC50 = - 5.7*10-6 M in Cal 33; being ΔIC50 the difference of IC50 between sequence 2 and BKM120 alone). CI values confirmed a synergistic interaction between the two drugs given sequentially cetuximab + BKM120 in both cell lines. Addition of RT ahead of all treatments did not add any anti-proliferative effect to the treatments on Cal 33. Of note, on Cal 27 the addition of RT to BKM120 increased the antiproliferative effect of this drug (p&amp;lt;0.05). Overall, preliminary data on protein expression indicated an upregulation of caspase 3 and 9 only in Cal 27 suggesting an apoptotic pathway activation after sequence 1 and 2, not seen in Cal 33. Moreover Akt was upregulated in Cal 27 after sequence 1 and 2. Analysis of pAkt is on going to verify if blocking of PI3KCA by BKM120 in our models could lead to a control of the feedback loop induced by mTORC1 inhibition. This may be supported by the observed upregulation of p4EBP1 (downstream) following sequence 1 and 2. Akt upregulation due to the treatments may also explain the lack of a significative effect of RT on cell proliferation, mainly in Cal 27 wild-type cells. Conclusions The results of this in vitro could serve as a basis for early clinical trials associating BKM120 and RT in locally advanced HNSCC, providing interesting biochemical markers to conduct personalised therapy. Citation Format: Laura Lattanzio, Federica Tonissi, Martino Monteverde, Luca Gianello, Elvio Russi, Marco C. Merlano, Cristiana Lo Nigro, Gerard Milano. Combination of PI3KCA targeting with irradiation: A preclinical study on head and neck cancer cell lines. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1876. doi:10.1158/1538-7445.AM2014-1876