Mutations In Squamous Cell Carcinoma Research Articles

Understanding PI3K/Akt/mTOR signaling in squamous cell carcinoma: mutated PIK3CA as an example.

Compared with those in adenocarcinoma, PIK3CA mutations are more common in squamous cell carcinoma (SCC), which arises from stratified squamous epithelia that are usually exposed to adverse environmental factors. Although hotspot mutations in exons 9 and 20 of PIK3CA, including E542K, E545K, H1047L and H1047R, are frequently encountered in the clinic, their clinicopathological meaning remains to be determined in the context of SCC. Considering that few reviews on PIK3CA mutations in SCC are available in the literature, we undertook this review to shed light on the clinical significance of PIK3CA mutations, mainly regarding the implications and ramifications of PIK3CA mutations in malignant cell behavior, prognosis, relapse or recurrence and chemo- or radioresistance of SCC. It should be noted that only those studies regarding SCC in which PIK3CA was mutated were cherry-picked, which fell within the scope of this review. However, the role of mutated PIK3CA in adenocarcinoma has not been discussed. In addition, mutations occurring in other main members of the PI3K-AKT-mTOR signaling pathway other than PIK3CA were also excluded.

Clinicopathological characterization of next-generation sequencing detected mutations in lung cancers-a single-center experience.

Despite many advances in molecular procedures many lung cancer patients do not receive full panel testing. This can limit the comprehensive understanding of their disease and potentially hinder personalized treatment options. In this retrospective analysis, we used results from next-generation sequencing (NGS) testing of 154 patients with adenocarcinoma (AC) or squamous cell carcinoma (SCC) of the lung treated at the University Hospital, Ludwig-Maximilians Universität (LMU) Munich between 2018 and 2021. We compared different clinicopathological features and patients' baseline characteristics with results of NGS testing. We used t-test and analysis of variance (ANOVA) to compare metric- and χ2-test and Fisher's exact test to compare categorical variables. NGS testing found mutations in 107 (69.5%) patients; 44 patients (28.6%) had more than one mutation. The majority (79.2%) of patients had AC and 64.9% were metastasized at diagnosis. Patients with detected mutations had significantly higher PD-L1 expression than those without mutations (36.4% vs. 19.2%, P=0.005). Mean PD-L1 expression also differed between different mutations ranging from 24.0% in EGFR to 56.8% in patients with MET alterations, and increased with the number of different mutations (P=0.07). EGFR mutations were significantly more common in females compared to males (22.9% vs. 9.5%, P=0.04) and PIK3CA mutations significantly more common in SCC (21.9% vs. 2.5%, P=0.004). We found 23 different mutations in AC and 13 different gene mutations in SCC. Mutation profiles differed by histological type and metastases status and were significantly associated with PD-L1 expression. In the context of limited resources, our results may help prioritize patient for testing when tissue material and funding is limited.

403 A novel IL36RN mutation in squamous cell carcinoma developed in pustular psoriasis

Squamous cell carcinoma is known to have various precursors and precancerous lesions. Although it is thought to be based on chronic intractable inflammation such as burn scars, intractable ulcers, lupus vulgaris and discoid lupus erythematosus, there are many unclear points about the mechanism leading to carcinogenesis. Psoriasis, a representative chronic intractable inflammatory skin disease, has enhanced epidermal turnover and is considered to be a state close to cancer, but there are not many cases in which squamous cell carcinoma actually develops. Pyoderma gangrenosum is one of the precancerous conditions, whereas pustular psoriasis, also characterized by neutrophil infiltration, is considered to be more rarely secondary to squamous cell carcinoma. We once reported a 61-year-old woman with pustular psoriasis lesions with squamous cell carcinoma (Kaminaka et al, 2010 in Japanese). Collecting the cases with skin malignant tumors secondary to psoriasis reported in Japan from 1990 to 2010, it was found that there are 3 other cases of pustular psoriasis with secondary squamous cell carcinoma. Since the association between generalized pustular psoriasis and the IL36RN gene mutation has been revealed, DNA was extracted from the skin biopsy and/or surgical specimens of these four cases that had already died, and the IL36RN gene mutations were searched. As a result, in all 4 cases, the T123M mutation already reported in generalized pustular psoriasis and the unreported novel mutation were found in homozygous, heterozygous, and mosaic. Although a structural analysis suggests any functional significance, in vitro analysis has not revealed any alteration on the function of IL-36 receptor antagonist by the novel mutation. Although the analysis of healthy, psoriasis and cancerous tissues has not been performed separately, the state of mutation differs depending on the section, suggesting that the presence of the novel mutation identified this time may be involved in canceration.

31764 LRP1B expression is correlated with age and perineural invasion in metastatic cutaneous squamous cell carcinoma: A pilot study

Introduction: There are 1,000,000 cases of cutaneous squamous cell carcinoma (SCC) in the United States annually. While only 2-5% of SCCs metastasize, those that do have a poor prognosis. A recent study by our group demonstrated that LRP1B is mutated in 37% of SCCs, making it one of the top six genes mutated in SCC. However, the biologic significance of LRP1B mutations in SCC is unknown.

113 The endogenous deaminase APOBEC3A readily localizes to the nucleus of cultured keratinocytes

Members of the APOBEC (apolipoprotein B mRNA editing enzyme, catalytic polypeptide) family of deaminases have been identified as potent mutagens in squamous cell carcinoma arising across all body sites. Previous work has shown that tissue damage-driven squamous cell carcinoma (SCC) arising in the skin of patients with the rare blistering genodermatoses recessive dystrophic epidermolysis bullosa (RDEB) are dominated by APOBEC-driven mutations as well as high mRNA levels of APOBEC3A. Current literature reports APOBEC3B (A3B) and not APOBEC3A (A3A) is capable of localizing to the nucleus of mammalian cells resulting in the notion that A3B and not A3A generates somatic mutations in SCC.

A New Epitope Selection Method: Application to Design a Multi-Valent Epitope Vaccine Targeting HRAS Oncogene in Squamous Cell Carcinoma

We developed an epitope selection method for the design of MHC targeting peptide vaccines. The method utilizes predictions for several clinical checkpoint filters, including binding affinity, immunogenicity, antigenicity, half-life, toxicity, IFNγ release, and instability. The accuracy of the prediction tools for these filter variables was confirmed using experimental data obtained from the Immune Epitope Database (IEDB). We also developed a graphical user interface computational tool called ‘PCOptim’ to assess the success of an epitope filtration method. To validate the filtration methods, we used a large data set of experimentally determined, immunogenic SARS-CoV-2 epitopes, which were obtained from a meta-analysis. The validation process proved that placing filters on individual parameters was the most effective method to select top epitopes. For a proof-of-concept, we designed epitope-based vaccine candidates for squamous cell carcinoma, selected from the top mutated epitopes of the HRAS gene. By comparing the filtered epitopes to PCOptim’s output, we assessed the success of the epitope selection method. The top 15 mutations in squamous cell carcinoma resulted in 16 CD8 epitopes which passed the clinical checkpoints filters. Notably, the identified HRAS epitopes are the same as the clinical immunogenic HRAS epitope-based vaccine candidates identified by the previous studies. This indicates further validation of our filtration method. We expect a similar turn-around for the other designed HRAS epitopes as a vaccine candidate for squamous cell carcinoma. Furthermore, we obtained a world population coverage of 89.45% for the top MHC Class I epitopes and 98.55% population coverage in the absence of the IFNγ release clinical checkpoint filter. We also identified some of the predicted human epitopes to be strong binders to murine MHC molecules, which provides insight into studying their immunogenicity in preclinical models. Further investigation in murine models could warrant the application of these epitopes for treatment or prevention of squamous cell carcinoma.

KRAS Mutations in Squamous Cell Carcinomas of the Lung.

KRAS is one of the most commonly mutated oncogenes in cancer, enabling tumor proliferation and maintenance. After various approaches to target KRAS have failed over the past decades, the first specific inhibitor of the p.G12C mutation of KRAS was recently approved by the FDA after showing promising results in adenocarcinomas of the lung and other solid tumors. Lung cancer, the most common cancer worldwide, is a promising use case for these new therapies, as adenocarcinomas in particular frequently harbor KRAS mutations. However, in squamous cell carcinoma (SCC) of the lung, KRAS mutations are rare and their impact on clinical outcome is poorly understood. In this review, we discuss the current knowledge on the prevalence and prognostic and predictive significance of KRAS mutations in the context of SCC.

Comparison of genetic mutations in squamous cell carcinoma and actinic keratosis of the forehead in the same patient using whole-genome sequencing.

Comparison of genetic mutations in squamous cell carcinoma and actinic keratosis of the forehead in the same patient using whole-genome sequencing.

High Rates of Ultraviolet-Signature Mutations in Squamous Cell Carcinomas of the Parotid Gland and Prognostic Implications.

In the absence of clear pathologic differences, clinical history may differentiate potential primary parotid squamous cell carcinomas (SCC) from metastases. The presence of an ultraviolet (UV) signature can distinguish between tumors of cutaneous and non-cutaneous origin. This study aimed to investigate rates of UV signature mutations in squamous cell carcinomas of the parotid gland as well as differences in clinical features between tumors of cutaneous and non-cutaneous origin. Clinical and pathologic data were collected from 71 patients with SCC involving the parotid gland, of which 48 had cutaneous, 10 had mucosal, and 13 had no history of SCC. In 34 available cases, genomic DNA was isolated from formalin-fixed paraffin-embedded tissue specimens and sequenced using a targeted hybrid capture 1213 gene panel. Tumor mutational burden and COSMIC (Catalogue of Somatic Mutations in Cancer) mutational signatures were calculated. Most (74%) were UV-positive. Patients with UV-positive tumors were significantly older, white, and had higher rates of sun exposure. Patients with UV-negative tumors had a significantly higher mortality rate and shorter time to death: 6 (67%) died of disease with a median time to death of 9months compared to 5 (20%) UV-positive patients who died of disease with a median time to death of 32months. Pathologic features did not significantly vary by clinical history or UV status. The presence of a UV-signature combined with clinical history can be used to determine the primary source of SCC involving the parotid gland. UV-positivity may reflect a less aggressive disease course in an older population.

Analysis of mutations in cutaneous squamous cell carcinoma reveals novel genes and mutations associated with patient-specific characteristics and metastasis: a systematic review.

Cutaneous squamous cell carcinoma (SCC) causes approximately 1,000,000 cases and 9000 deaths each year in the United States. While individual tumor sequencing studies have discovered driver mutations in SCC, there has yet to be a review and subsequent analysis synthesizing current studies. To conduct a comprehensive synthesis and analysis of SCC sequencing studies with individual patient-level data, a comprehensive literature search was performed. Statistical analyses were performed to identify trends. Studies meeting inclusion criteria included a total of 279 patients (189 localized SCCs, 90 metastatic SCCs). Several mutations were correlated with demographic characteristics (TP53, MLL4, BRCA2, COL4A1). TP53, TERT, SPEN, MLL3, and NOTCH2 mutations were significantly more likely to be found in metastatic versus localized SCCs even after the Bonferroni correction for multiple comparisons. Silent mutations were found more in localized SCCs than metastatic SCCs, and nonsense mutations were found more in metastatic SCCs than localized SCCs (p = 0.0003 and p = 0.04, respectively). Additional mutations were identified that have not yet been explored in SCC including AHNAK2, LRP1B, TRIO, MDN1, COL4A2, SVIL, VPS13C, DST, DMD, and DYSF. Overall, novel mutations were identified and differences between mutation patterns in localized and metastatic SCCs were found. These findings may have clinical applications.

S1554 Unusual Mutation in Squamous Cell Carcinoma of Pancreas

INTRODUCTION: Pancreatic neoplasm is an aggressive malignant tumor of the digestive tract and a leading cause of death related worldwide. Squamous cell carcinoma of pancreas (SCCP) currently has an annual incidence rate of 0.02 cases per 100,000. The diagnosis is made only after excluding other neoplastic lesions of the pancreas that contain squamous epithelial components. CASE DESCRIPTION/METHODS: A 72 years old male with a history of diabetes mellitus, hypertension and a resected colorectal cancer that three years after resection, developed fatigue, unintentional weight loss, asthenia and anorexia. A contrast Abdominal CT revealed hepatomegaly suggestive of metastatic disease, intrahepatic and extrahepatic biliary duct dilation, and a pancreatic tail mass. CT guided biopsy of liver lesion showed metastatic squamous cells. PET scan identified a hypermetabolic, 3cm soft tissue mass in the left upper quadrant of the abdomen inseparable from the tail of the pancreas. Endoscopic ultrasound fine needle aspiration revealed a moderately differentiated SCCP. Next-generation sequencing came out with six genomic mutations, KRAS, FGFR1, NKX2-1, PBRM1, SPEN, and TP53. The patient was admitted to an oncologic unit where Nanoparticle albumin-bound paclitaxel-gemcitabine regimen was administered. However, due to complications including sepsis, and multi-organ failure, therapy was discontinued. Unfortunately, the patient succumbed to the latter. DISCUSSION: SCCP is a rare entity as squamous cells are naturally absent from the pancreas. However, these can be seen in conditions such as chronic pancreatitis, primary or metastatic carcinoma, and squamous metaplasia related to pancreatic or biliary duct stent placement. Squamous tumours are enriched for TP53 and KDM6A mutations, upregulation of the TP63 transcriptional network, hypermethylation of pancreatic endodermal cell-fate determining genes and have a poor prognosis. Thus, identifying patients who are at high risk to develop pancreatic cancer and who should undergo surveillance has to be a priority. In addition, there is a need to develop tumor markers for early detection, monitoring and treatment purposes. Precursor lesions might represent the opportunity to cure pancreatic neoplasia. With the integration of high throughput sequencing to the clinical practice, valuable information will be obtained. Consequently, providing better understanding of its pathogenesis, improving therapies alternatives and outcomes of pancreatic carcinomas.Figure 1.: Pancreas moderately differentiated Squamous Cell Carcinoma.Figure 2.: Multiple, hypermetabolic, large hepatic lesions, and a 3 cm soft mass in the left upper quadrant, inferior to the stomach and anterior to the spleen inseparable from the tails of pancreas.

Abstract 4903: Minimal mutational determinants of human squamous cell carcinoma

Abstract Dozens of driver mutations and copy number changes have been implicated in human squamous cell carcinomas (SCCs), and each tumor harbors multiple putative driver mutations. However, the minimal set of mutations sufficient to transform a normal keratinocyte into squamous cell carcinoma is unknown. By analyzing TCGA data and previously published datasets, we have identified common combinations of driver mutations in SCCs. Among the most common driver events are mutations in TP53, CDKN2A, and NOTCH1. Using CRISPR editing at endogenous loci in primary human keratinocytes, we demonstrate that no single driver mutation is sufficient to transform keratinocytes, and in fact many single gene mutations appear toxic to keratinocytes. The combination of loss of function mutations in TP53 and CDKN2A are sufficient to immortalize both skin and oral primary human keratinocytes in 2D culture, and confer a selective advantage in competition assays. Simultaneous mutation of TP53, CDKN2A, and NOTCH1 demonstrates a very similar phenotype in 2D culture as mutation of TP53 and CDKN2A alone. However, using 3D organotypic squamous epithelial cultures consisting of genome-edited keratinocytes grown on decellularized dermis impregnated with fibroblasts and grown at an air-liquid interface demonstrates that keratinocytes with TP53 and CDKN2A mutation alone are sufficient to induce dysplasia, whereas keratinocytes harboring TP53, CDKN2A, and NOTCH1 mutation exhibit an SCC like phenotype including invasion through the basement membrane. RNAseq analysis demonstrates that the transition to SCC by NOTCH1 loss involves a partial-EMT like program. Targeted hybrid capture sequencing of edited keratinocytes revealed no other driver mutations or copy number changes other than the experimentally induced ones, consistent with the notion that TP53, CDKN2A, and NOTCH1 mutations alone are sufficient to reprogram normal keratinocyte into their malignant counterparts. Thus, despite a high mutation burden and frequent chromosomal instability, as few as three mutational events appear to be sufficient to induce SCC. Citation Format: Vicente Planells-Palop, Angie Koo, Heydi Malave, Katharine Lee, Aaron Tward. Minimal mutational determinants of human squamous cell carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4903.

Abstract B40: Minimal mutational determinants of human squamous cell carcinoma

Abstract Dozens of driver mutations and copy number changes have been implicated in human squamous cell carcinomas (SCCs), and each tumor harbors multiple putative driver mutations. However, the minimal set of mutations sufficient to transform a normal keratinocyte into squamous cell carcinoma is unknown. By analyzing TCGA data and previously published datasets, we have identified common combinations of driver mutations in SCCs. Among the most common driver events are mutations in TP53, CDKN2A, and NOTCH1. Using CRISPR editing at endogenous loci in primary human keratinocytes, we demonstrate that no single driver mutation is sufficient to transform keratinocytes, and in fact many single gene mutations appear toxic to keratinocytes. The combination of loss-of-function mutations in TP53 and CDKN2A is sufficient to immortalize both skin and oral primary human keratinocytes in 2D culture and confer a selective advantage in competition assays. Simultaneous mutation of TP53, CDKN2A, and NOTCH1 demonstrates a very similar phenotype in 2D culture as mutation of TP53 and CDKN2A alone. However, using 3D organotypic squamous epithelial cultures consisting of genome-edited keratinocytes grown on decellularized dermis impregnated with fibroblasts and grown at an air-liquid interface demonstrates that keratinocytes with TP53 and CDKN2A mutation alone are sufficient to induce dysplasia, whereas keratinocytes harboring TP53, CDKN2A, and NOTCH1 mutation exhibit an SCC-like phenotype, including invasion through the basement membrane. RNAseq analysis demonstrates that the transition to SCC by NOTCH1 loss involves a partial EMT-like program. Targeted hybrid capture sequencing of edited keratinocytes revealed no other driver mutations or copy number changes other than the experimentally induced ones, consistent with the notion that TP53, CDKN2A, and NOTCH1 mutations alone are sufficient to reprogram a normal keratinocyte into SCC. Thus, despite a high mutation burden and frequent chromosomal instability, as few as three mutational events appear to be sufficient to induce SCC. Citation Format: Vicente Planells-Palop, Angie Koo, Heydi Malave, Katharine Lee, Aaron Tward. Minimal mutational determinants of human squamous cell carcinoma [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr B40.

Characterization of Squamous Cell Lung Cancers from Appalachian Kentucky.

Lung cancer is the leading cause of cancer mortality in the United States (U.S.). Squamous cell carcinoma (SQCC) represents 22.6% of all lung cancers nationally, and 26.4% in Appalachian Kentucky (AppKY), where death from lung cancer is exceptionally high. The Cancer Genome Atlas (TCGA) characterized genetic alterations in lung SQCC, but this cohort did not focus on AppKY residents. Whole-exome sequencing was performed on tumor and normal DNA samples from 51 lung SQCC subjects from AppKY. Somatic genomic alterations were compared between the AppKY and TCGA SQCC cohorts. From this AppKY cohort, we identified an average of 237 nonsilent mutations per patient and, in comparison with TCGA, we found that PCMTD1 (18%) and IDH1 (12%) were more commonly altered in AppKY versus TCGA. Using IDH1 as a starting point, we identified a mutually exclusive mutational pattern (IDH1, KDM6A, KDM4E, JMJD1C) involving functionally related genes. We also found actionable mutations (10%) and/or intermediate or high-tumor mutation burden (65%), indicating potential therapeutic targets in 65% of subjects. This study has identified an increased percentage of IDH1 and PCMTD1 mutations in SQCC arising in the AppKY residents versus TCGA, with population-specific implications for the personalized treatment of this disease. Our study is the first report to characterize genomic alterations in lung SQCC from AppKY. These findings suggest population differences in the genetics of lung SQCC between AppKY and U.S. populations, highlighting the importance of the relevant population when developing personalized treatment approaches for this disease.

1715P - PIK3CA mutation and PDL1 expression in lung squamous cell carcinoma surgically resected

Background: Squamous-cell carcinoma (SCC) of the lung is the second most frequent histology in non-small cell lung cancer (NSCLC). Over the last decade new approaches targeting specific pathways in NSCLC have emerged but very few advances were made in its treatment. The PI3K-AKT-mTOR pathway is implicated in multiple cancer processes and PIK3CA mutations are being investigated in SCC as potential therapeutic target. The aim of the study was to evaluate the histological characteristics, mutations in PIK3CA and PD-L1 expression in these tumors. Methods: Surgically resected lung SCC samples (FFPE) from 100 patients, stage I-III, were included in this study. Clinicopathologic characteristics included tumor size, TNM, smoking status, lymphovascular and pleural invasion, histopathological grade, stromal lymphoplasmacytic reaction and type of tumoral growing. DNA was isolated from 92 samples according to standard procedures and PIK3CA mutation analysis was done using Cobas 4800 platform. PD-L1 expression was analyzed in 74 cases by immunohistochemistry with PDL1 22C3 pharmDX assay. The PD-L1 expression was evaluated by tumor proportion scores (TPS) as IASLC guidelines. Results: The mean age was 68 years (53-86), 14 females and 86 males. About staging: 53 patients had stage I, 27 stage II, and 19 stage III. 53% and 35% showed vascular and pleural invasion respectively. Low to moderate stromal lymphoplasmacytic reaction was found in 34% and severe in 11%. PI3KCA mutation was found in 9/92 (9,8%) patients: E545X (n = 2), E542K (n = 5), H1047X (n = 1), C420R (n = 1). PD-L1-expression was found in 31 out of 74 cases (42%): 14 cases with TPS between 1-49%; 17 cases with TPS >50%. 5/9 (55%) of PIK3CA mutated cases were PD-L1 positive (2 of them >50%). In PIK3CA non-mutated cases 26 out of 67 (39%) showed PD-L1 expression: 11 cases with TPS between 1-49%; 15 cases with TPS >50%. Conclusions:PIK3CA mutation was found in 9,8% of SCC of the lung, most of them in exon 9. PD-L1 expression was found in 42% of the SCC in our series. 55% of PIK3CA mutated patients were positive for PD-L1 expression. No correlation has been found between PD-L1 expression and PIK3CA mutation in SCC. It is important to know more about the relation of these factors to select the patients for immunotherapy and new target agents. Legal entity responsible for the study: IIS Funding: None Disclosure: All authors have declared no conflicts of interest.

EGFR analysis of 21,039 patients with NSCLC: Age-related gradual increase of the L858R mutation frequency in adenocarcinomas and high occurrence of ex19del/L858R mutations in squamous cell carcinomas from females and/or nonsmokers.

9040 Background: EGFR testing in Russia is carried out upon the patronage of Russian Society of Clinical Oncology (RUSSCO), and the results are accumulated in a centralized database. Squamous cell carcinomas (SCC) constitute 60-70% of NSCLC incidence in Russia, however physicians are often discouraged to send NSCLC-SCC for EGFR testing due to low frequency of mutations. Methods: We considered all NSCLC patients analyzed by means of PCR for the presence of EGFR mutations (ex19del and L858R) within years 2012-2017. Results: 21,039 NSCLC patients were tested. EGFR analysis was successful in 20,768 patients (98.7%). EGFR mutations were detected in 3566/17717 (20.1%) adenocarcinomas (AdCa) of the lung (ex19del: 2203 (12.4%); L858R: 1363 (7.7%)). There was an evident age-related increase in the frequency of L858R substitution in AdCa patients (p =0.000, Table). This set of patients included 1,139 NSCLC-SCC cases, and the EGFR mutation was observed in 41 (3.6%) subjects. Among 189 females with NSCLC-SCC, ex19del or L858R were detected in 25 (13.2%) cases. Stratification by smoking status revealed EGFR mutation in 19/242 (7.9%) non-smokers. Conclusions: Elderly NSCLC patients have particularly increased probability to be diagnosed with L858R mutation. In the real-world setting, patients with NSCLC-SCC may have high frequency of EGFR mutations, either due to imprecise histological subtyping or due to yet unknown reasons. All female and non-smoking patients with NSCLC have to undergo EGFR testing irrespectively of tumor histology. [Table: see text]

EGFR mutation in squamous cell carcinoma of the lung: does it carry the same connotation as in adenocarcinomas?

BackgroundEGFR tyrosine kinase inhibitors (TKIs) have greatly improved the outcomes of EGFR mutation-positive adenocarcinomas of the lung. In contrast, the significance of EGFR mutation in metastatic squamous cell carcinoma (SCC) of the lung has been debated.MethodsAll patients with metastatic SCC who underwent EGFR mutation testing at our center from 2010 to 2015 were included for analysis. EGFR kinase domain mutations were tested using Taqman-based real-time polymerase chain reaction (PCR). Response assessment was done using Response Evaluation Criteria In Solid Tumors (RECIST) 1.1. Kaplan–Meier method was used for calculating progression-free survival (PFS) and overall survival (OS).ResultsEGFR mutation was detected in 29 out of 639 patients with SCC. Furthermore, 19 out of the 29 patients received TKIs at some point during their treatment. TKI therapy led to a partial response in 5 out of 19 patients and stable disease in 4 out of 19 patients. The median PFS of patients treated with TKIs was 5.0 months. The median OS of the whole EGFR-positive SCC cohort was 6.6 months. On univariate analysis, patients having received TKI therapy was the only factor associated with a significantly better OS of 13.48 months versus 2.58 months (P=0.000). On multivariate analysis, patients receiving TKI therapy, Eastern Cooperative Oncology Group–Performance Scale (ECOG-PS) score <2, EGFR exon 19 mutation and nonsmoking status were associated with significantly better OS.ConclusionEGFR mutation in SCC of the lung predicts a better outcome if the patient is given TKI, but it may be inferior to the outcomes seen in EGFR-positive adenocarcinomas treated with TKI.

P1.02-041 Characterization of MET-N375S as an Activating Mutation in Squamous Cell Carcinoma of the Lung

Over the years, significant progress has been made in the treatment of lung carcinoma. While targeting EGFR mutations in the tyrosine kinase domain and EML4-ALK rearrangements have yielded impressive therapeutic gains in lung adenocarcinoma; the rarity of genetic aberration in squamous cell carcinoma (SCC) has restricted the use of molecular-targeting agents. Next-Generation sequencing analysis has identified a high frequency of c-MET mutation in Asian lung SCC specimens, in particular the MET-N375S mutant. This study aims to characterize the functional significance and therapeutic implications of MET-N375S in lung SCC cells. MET (N375S) mutation in tumor tissues was verified with droplet digital PCR. c-MET mutant expressing clones were generated through site-directed mutagenesis and single cell clonal selection. The impact of MET-N375S in lung SCC cells was characterized by defining the downstream effectors (Proteome profiling), biological functions (anchorage-independent growth, invasion and migration assays), transciptomic regulation (RNAseq) and protein-protein interaction (SILAC). Novel binding partners of MET-N375S was verified using co-immunoprecipitation (co-IP) and proximity ligation assay (PLA). Sensitivity of c-MET mutant to various kinase inhibitors was determined with CellTiter-Glo assay. MET (N375S) mutation was confirmed in 9/45 lung SCC specimens (20%). Ectopic expression of MET-N375S in lung SCC cells significantly elevated the activation of downstream Src, p38 and ERK1/2 kinases, increased hsp27 expression, while enhanced migratory, invasive and anchorage-independent colony forming ability in vitro. Despite so, comparative transcriptomic analysis revealed that epithelial-mesenchymal signature genes were not induced in cells expressing mutant c-MET. On the contrary, SILAC and co-IP analyses on the MET-N375S interactome demonstrated an increase in binding affinity towards receptor tyrosine kinases (RTKs) as compared to wild type c-MET, which was confirmed with in situ PLA. Moreover, MET-N375S augmented in vitro sensitivity to selective MET inhibitors. These findings suggest the role of MET-N375S as an activating mutation that strongly enhance malignant transformation and metastatic potential in lung SCC cells. Mechanistically, the dysregulation of various oncogenic events could be associated with the formation of heterodimers with RTKs. Clinically, MET-N375S could be utilized as a potential predictive biomarker for patients with advanced SCC of the lung to be treated with selective MET inhibitors.

1251P - EGFR mutation in squamous cell carcinoma of lung - Does it carry the same connotation as in adenocarcinomas?

1251P - EGFR mutation in squamous cell carcinoma of lung - Does it carry the same connotation as in adenocarcinomas?

Identification of differential genetic mutations in squamous cell carcinoma of pancreas by using HTS after in-solution hybrid capture

Identification of differential genetic mutations in squamous cell carcinoma of pancreas by using HTS after in-solution hybrid capture