EGFR detection by liquid biopsy: ripe for clinical usage.

Introduction: With the International Association for the Study of Lung Cancer (IASLC) recommendations promoting liquid biopsy as a primary detection tool, a new era of research has begun. The authors aimed to study the concordance of plasma genotyping platforms against the tissue gold standard. Methods: 184 patients with non-small cell lung cancer underwent EGFR genotyping using Cobas, droplet digital polymerase chain reaction (ddPCR) and Therascreen assays from 2019-2020. Results: Of 184 cases, 70 were positive by Cobas, 51 by ddPCR and 69 by Therascreen. The sensitivity of Cobas was 97.1% and the sensitivity of ddPCR was 71%. Receiver operating characteristic analysis showed an area under the curve of 0.977 for Cobas and 0.846 for ddPCR. Conclusion: In line with the FLAURA trial of osimertinib making its way to first-line and given the IASLC recommendations, it is important to understand the attributes of these tests to initiate appropriate treatment.

Lay abstract Lung cancer is one of the most common malignancies and has been known to have a dismal outcome. However, owing to evolution in the knowledge of disease biology and processes, many molecules have been discovered that can be used in targeted therapy. To institute this modality of treatment, detection of alterations in these specific molecules, namely: EGFR, ALK, ROS1, RET, MET, KRAS G12C, BRAF V600E, NTRK1, NTRK2, NTRK3 and ERBB2 is necessary. This has traditionally been done using single-gene assays, which require more tissue. This is a major limitation in cases of non-small cell lung carcinoma, as the biopsies are small. Hence, new technologies like next-generation sequencing have emerged that offer a one-stop solution for these cases. In cases where tissue is very scant, the use of peripheral blood has now been recommended by international guidelines for primary detection of these molecular alterations. This article describes the concordance of tissue-based detection and blood-based detection using three different assays, for the detection of EGFR alterations. Although promising results were obtained largely for blood-based assays, liquid and tissue biopsies are complementary.

Are all ALK variants created equal? Clinicopathologic features and outcomes: a propensity-matched study.

Anaplastic lymphoma kinase (ALK) rearranged NSCLC comprises a molecularly distinct subgroup occurring in 10% cases. Various EML4-ALK and non EML4 variants are known to occur which can be detected only on NGS and show differential TKI responses. 113 ALK-IHC positive cases were subjected to a custom panel-based NGS for detection of ALK variants. Clinicopathologic features and outcomes were studied and propensity-matched analysis was done. The median age of the overall cohort was 53 years. 91 (80.5%) cases were NGS positive, the most common being EML4-ALK (90, 98.9%) cases. The most common EML4 variant was Variant 1 (40, 35%) cases, Variant 3 (28, 25%) cases, and Variant 2 (17, 15%) cases. One novel EML4-ALK variant was also encountered which was found to be intrinsically resistant to crizotinib. On pre-weight-adjusted comparison, Variant 1 group had a higher occurrence of brain and extrathoracic metastases. The median OS was 44 months for the entire cohort. 49 patients received crizotinib as first-line TKI. Among these, the median OS for Variant 2 was not reached; it was 38 months and 24 months for Variant 1 and Variant 3, respectively. The median PFS for crizotinib treated patients was 8.3 months (Variant 2: 11 months, Variant 1: 8 months, and Variant 3: 9 months). On propensity-matched analyses, there was no difference in OS and PFS between Variant 1 and Variant 3, with higher HR for Variant 3. We present a large data set evaluating clinical and outcome differences between ALK variants. The unique standpoint of this study involves the propensity-weighted model to account for differences among the groups, with no prognostic differences between Variant 1 and Variant 3, which is distinct from literature.

Extradural spinal melanoma: is it primary or metastatic? A case report with a brief review of literature.

Melanocytic lesions involving the central nervous system are extremely rare and pose a diagnostic challenge owing melanoma being the third most common malignancy metastasizing to the spine. Morphology and immunohistochemistry are identical in both primary and secondary cases, and hence may not help in rendering a final diagnosis. Molecular alterations involving melanomas of the spine and melanomas elsewhere are distinct and help establish the appropriate diagnosis. We report an interesting case where molecular profiling of the tumor tissue helped render the final diagnosis.

COVID-19 and Cancer: A Comparison of the Two Important Pandemic Waves in an Indian Cancer Patients' Cohort.

Ullas BatraIt is well known that patients with cancer are at an increased risk of severe COVID-19. There are no reports that depict the differences in outcomes in cancer patients between the two waves of the pandemic. This is a real-world experience aimed at characterizing the differences in demographics, clinical features, treatment details, and outcomes in COVID-19-positive cancer patients between the two pandemic waves. This was a prospective study of all COVID-19-positive cancer patients attending our specialty out-patient department at Rajiv Gandhi Cancer Institute and Research Centre between March 2020 and November 2020 (1st wave) and April 2021 and June 2021 (second wave). All patients diagnosed to have COVID-19 by real-time polymerase chain reaction (RT-PCR) with a biopsy-proven solid organ malignancy attending the medical oncology out-patient department were included during both the waves. A total of 300 patients with proven SARS-CoV-2 infection by either RT-PCR or cartridge based nucleic acid amplification test were encountered, of which 123 were encountered during the first wave of the pandemic and 177 during the second wave. The case fatality rate of the first wave was 9.8%, with a 15-day case fatality rate of 5.6%, whereas for the second wave, it was 13% and 7.2%, respectively. Twelve patients succumbed to COVID-19 disease in the first wave and 23 succumbed in the second. There were no statistically significant correlations; however, the death in the second wave tended to occur more in younger male patients, with comorbidities and history of smoking. There was no relation with ongoing cancer-directed treatment or chemotherapy. Our study is unique in comparing characteristics of the two most important COVID-19 waves and treatment patterns in cancer patients from a single center. The second wave showed a higher CFR, hospital admission rate, and higher frequency of respiratory complications; however, there was no relation to cancer-directed therapy and COVID-19, thus reiterating the fact that cancer treatment should not be halted in the event of a COVID-19 infection.

AI-based pipeline for early screening of lung cancer: integrating radiology, clinical, and genomics data.

Background: The prognosis of lung carcinoma has changed since the discovery of molecular targets and their specific drugs. Somatic Epidermal Growth Factor Receptor (EGFR) mutations have been reported in lung carcinoma, and these mutant proteins act as substrates for targeted therapies. However, in a resource-constrained country like India, panel-based next-generation sequencing cannot be made available to the population at large. Additional challenges such as adequacy of tissue in case of lung core biopsies and locating suitable tumour tissues as a result of innate intratumoral heterogeneity indicate the necessity of an AI-based end-to-end pipeline capable of automatically detecting and learning more effective lung nodule features from CT images and predicting the probability of the EGFR-mutant. This will help the oncologists and patients in resource-limited settings to achieve near-optimal care and appropriate therapy. Methods: The EGFR gene sequencing and CT imaging data of 2277 patients with lung carcinoma were included from three cohorts in India and a White population cohort collected from TCIA. Another cohort LIDC-IDRI was used to train the AIPS-Nodule (AIPS-N) model for automatic detection and characterisation of lung nodules. We explored the value of combining the results of the AIPS-N with the clinical factors in the AIPS-Mutation (AIPS-M) model for predicting EGFR genotype, and it was evaluated by area under the curve (AUC). Findings: AIPS-N achieved an average AP50 of 70.19% in detecting the location of nodules within the lung region of interest during validation and predicted the score of five lung nodule properties. The AIPS-M machine learning (ML) and deep learning (DL) models achieved AUCs ranging from 0.587 to 0.910. Interpretation: The AIPS suggests that CT imaging combined with a fully automated lung-nodule analysis AI system can predict EGFR genotype and identify patients with an EGFR mutation in a cost-effective and non-invasive manner. Funding: This work was supported by a grant provided by Conquer Cancer Foundation of ASCO [2021IIG-5555960128] and Pfizer Products India Pvt. Ltd.

A novel EML4-NTRK3 fusion in lung adenocarcinoma with dramatic response to entrectinib.

ABSTRACT: In-frame fusions in NTRK genes, with intact kinase domain, have been reported to occur at higher frequencies in rare tumors like infantile fibrosarcoma, congenital mesoblastic nephroma, and secretory carcinoma, whereas they occur at very low frequencies in common malignancies like NSCLC and colon cancers (0.1%-1%). Despite the rare occurrence, these alterations have gained importance owing to approval of drugs like entrectinib and larotrectinib targeting the kinase domain of the gene. More than 50 fusion partners have been described, and only in-frame fusions result in constitutive ligand-independent kinase activity leading to oncogenesis. The commonly reported NTRK fusions in the lung include SQSTM1-NTRK1, ETV6-NTRK3, and SQSTM1-NTRK3. Detection of these rests on the use of conventional modalities like Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH); however, accurate characterization requires direct sequencing methods. We report an interesting case of an NTRK fusion-positive NSCLC, exhibiting good response to entrectinib.

KRAS mutated Non-Small Lung Carcinoma: A Real World Context from the Indian subcontinent.

BACKGROUND: KRAS, although a common variant of occurrence (~20% of non-small-cell lung carcinoma [NSCLC]) has been untargetable, owing to the molecular structure which inherently prevents drug binding. KRAS mutations in NSCLC are associated with distinct clinical profiles including smokers and mucinous histology. KRAS G12C mutations account for ~40% KRAS altered NSCLC, but NSCLC being a geographically diverse disease, the features may be distinct in this part of the world. This is a single-center experience of KRAS-mutated NSCLC including clinical, imaging, pathologic features, and treatment patterns and outcomes. METHODS: This is a single-center retrospective study of KRAS-mutated NSCLC. The clinicopathological features and outcomes were retrieved and collated from the medical record archives of the hospital. RESULTS: Fifty (30.6%) patients with advanced-stage NSCLC with alterations in the KRAS gene were enrolled in the 163 patients who were tested for KRAS alterations. The median age was 61 years. Molecular detection revealed three main types of KRAS mutations viz-a-vis: G12C in 17 (34%), G12V in 9 (18%), and G12D in 6 (12%) patients. Comparing G12C versus the non-G12C mutated cases, co-mutations were common in the non-G12C subgroup (p < 0.05). Among the 36, who were treated at our center, all received chemotherapy as the first line with a median progression-free survival (PFS)of 5.4 months. The PFS of G12C was higher than the non-G12C subgroup (6.4 vs 3.8 months). CONCLUSION: This is the largest single-center experience from the Indian subcontinent for KRAS-mutated NSCLC with distinct clinical features. It highlights the unmet need for G12C inhibitors in our country, where prevalence is equivalent to the West.

Primary pulmonary NUT midline carcinoma: An elusive and a rare diagnostic entity.

Nuclear protein in testis (NUT) midline carcinoma is a poorly differentiated tumor, is more common in midline anatomic sites, and involves young adults and children mainly. Primary pulmonary NUT midline carcinoma (NMC) is a rare and poorly defined entity in the prevailing literature. Being a highly aggressive and fatal neoplasm, it gets incumbent for the oncologists and the pathologists to be aware of this entity as it holds distinct management protocol and prognosis. Currently, BET inhibitors (BETi) and histone deactylase inhibitors have shown promising results as targeted therapies in clinical trials in head and neck NMC. We present a case report of NMC of primary pulmonary location in a young male with widespread bony metastasis.

Tri-modality therapy in advanced esophageal carcinoma: long-term results and insights from a developing world, institutional cohort.

OBJECTIVE: To evaluate treatment outcomes in patients from a low-middle income country (LMIC) with esophageal carcinoma who underwent esophagectomy after neoadjuvant chemoradiation (NACRT/S). METHODS: Between 2010 and 2020, 254 patients (median follow-up: 53 months) met our inclusion criteria. Out-of-field nodal regions were determined by reviewing individual radiotherapy plans. Cox regression modelling was performed to analyze overall survival (OS) and recurrence-free survival (RFS), while pathological complete response (pCR) prediction utilized Poisson regression. RESULTS: The median OS was 71.4 months (interquartile range: 19.6-∞), RFS did not reach the median and pCR rate was 46%. On multivariable Cox regression, BMI [0.93 (0.89-0.98); 0.94 (0.89-0.99)] and absence of out-of-field node with extranodal extension (ENE)[0.22 (0.09-0.53); 0.30 (0.12-0.75)] influenced OS and RFS, respectively. Age [1.03 (1.01-1.06)], nodal stage [cN2-3 vs cN0: 2.67 (1.08-6.57)] and adventitial involvement [2.54 (1.36-4.72)] also influenced OS, while involved margins [3.12 (1.24-7.81)] influenced RFS. On multivariable Poisson regression, non-CROSS-chemotherapy regimens [0.65 (0.44-0.95)] and residual primary disease on pre-surgical imaging [0.73 (0.57-0.93)] were significantly associated with pCR. The most frequently involved in-field and out-of-field nodal regions were the periesophageal and perigastric (greater and lesser curvature) regions, respectively. CONCLUSION: NACRT/S is feasible and effective in patients from LMIC. Out-of-field ENE merits further investigation as a prognostic factor since it significantly influenced both OS and RFS. ADVANCES IN KNOWLEDGE: The results of clinical trials are replicable in LMICs. Out-of-field ENE is an independent prognostic factor for OS and RFS.

Next generation sequencing for detection of EGFR alterations in NSCLC: is more better?

AIMS: The emergence of sophisticated next generation sequencing (NGS) based technologies in routine molecular diagnostics has paved the way for robust and accurate detection of variants which may otherwise be missed on single gene testing. This study aims at highlighting the same premise in EGFR mutated non-small cell lung carcinoma (NSCLC). METHODS: 1350 cases of NSCLC were screened, of which 490 EGFR mutated cases were taken. The clinical records and molecular features were evaluated retrospectively to determine those cases which were missed on single gene testing. RESULTS: Among these 490 cases, there were 11 (2.2%) cases which tested negative on single gene testing using polymerase chain reaction (therascreen). These were then subjected to NGS based testing and were positive for 13 different EGFR mutations. Five out of the 11 cases received EGFR tyrosine kinase inhibitor (TKI) based on the NGS test outcome. Four cases with exon 20 insertion mutations were not offered TKI as these mutations are known to be intrinsically resistant to TKI therapy. The five patients who have been treated with TKI have shown fair response and have not progressed to date. CONCLUSIONS: We demonstrated a potentially preferable way to profile treatment-naïve patients with NSCLC by NGS and from our early experience in EGFR mutant cases, the advantages of NGS over single gene testing is clearly evident.

Machine learning-based algorithm demonstrates differences in del19 and L858R EGFR subgroups in non-small cell lung cancer: a single center experience.

BACKGROUND: Exon del19 and L858R mutations account for 90% of EGFR mutant non-small cell lung cancer (NSCLC). LUX lung 3 and 6 initially reported a survival difference between these two. However, other studies did not demonstrate the same. By using machine learning (ML), it is possible to discover novel patterns for cancer susceptibility, recurrence, prognostication, and therapy. We evaluate the effect of these two molecular subtypes on overall survival/progression-free survival (OS/PFS). METHODS: 413 patients with stage IV EGFR mutant NSCLC were analyzed for clinicopathologic features, treatment details, and survival outcome. PFS prediction models were built using ensemble decision trees, and random forest. Ensemble decision trees were built and validation was performed using survival analysis. Clustering regression techniques were then applied to train and test the prediction of the 1st PFS of patients. RESULTS: The median age of the cohort was 59 years comprising 53% males and 47% females. 275 (66.5%) patients showed a del19 mutation type and 138 (33.5%) harbored L858R. After clustering, the most important variables were age (P<0.05), ECOG performance status (PS) (P<0.04), PDL1 (P<0.09), smoking status (P<0.01) and to a lesser extent, number of extrathoracic metastasis (ETM) sites (median 1.2, P<0.06), brain metastasis (P<0.06) and gender (P<0.08). The prediction for 1st PFS for del19 showed mean absolute error of 2.6 months and 4.72 months for L858R. The accuracy was 79.8% with 82% sensitivity, 79% specificity and AUC: 0.72. The precision was 92% with a Mathews correlation coefficient of 0.59. CONCLUSION: This study used machine learning modeling with fair accuracy to demonstrate that ECOG PS, age at diagnosis, and smoking status are the three main predictive factors of PFS in these patients.

Founder BRCA1 mutations in Nepalese population.

BACKGROUND: Founder mutation is a heritable genetic alteration observed with high frequency in a geographically and culturally isolated population where one or more ancestors becomes the forebearer of the altered gene. The current study reports two founder mutations in the BRCA1 gene in the Nepalese people. METHODS: Germline BRCA testing in all surface epithelial ovarian cancers and the selected case of breast, prostate, and pancreatic cancers has been the standard practice from 2016 to 2021. One thousand one hundred thirtythree probands were screened for germline BRCA variants by next generation sequencing. The variants were classified as per the American Society of Medical Genetics and Genomics recommendations. Pathogenic (class V) and likely pathogenic (class IV) were considered clinically relevant and utilized for cascade screening. RESULTS: Nepalese population made up a subcohort of 5.12% (58/1,133) of probands tested for germline BRCA1/2 variants. Twenty-seven of these 58 tested harbored pathogenic genetic alterations in BRCA1/2 genes, with 23 being BRCA1 mutant. Sixteen of 23 BRCA1 mutant cases shared one common pathogenic mutation c.2214_2215insT (p.Lys739Ter) (NM_007294.4). Additionally, a second highly recurrent mutation in BRCA1 gene c.5068A>T (p.Lys1690Ter) (NM_007294.4) was noted in six patients from this population. CONCLUSIONS: The overwhelming abundance of the above two variants in a geographically confined population confers these two genetic alterations a status of founder mutations amongst the people of Nepal. A more extensive population-based study to reaffirm these findings will help establish a dual site-specific germline testing similar to the "Multisite-3-assay" in Ashkenazi Jews as the primary screening tool, especially in a resource-constrained environment.

IHC versus FISH versus NGS to detect ALK gene rearrangement in NSCLC: all questions answered?

AIMS: Anaplastic lymphoma kinase (ALK) rearranged non-small cell lung carcinoma (NSCLC) is a distinct molecular subtype and rapid approval of ALK tyrosine kinase inhibitors (TKIs) has necessitated rapid and sensitive diagnostic modalities for the detection of this alteration. Gene rearrangements can be identified using many techniques including fluorescence in situ hybridisation (FISH), reverse transcriptase-PCR, next-generation sequencing (NGS) and immunohistochemistry (IHC) for fusion oncoprotein expression. We aimed to determine the concordance between IHC, FISH and NGS for ALK biomarker detection, and determine differences in sensitivity, and survival outcomes. METHODS: We analysed the concordance between IHC using D5F3 monoclonal antibody, FISH (break-apart) and NGS using a custom panel containing 71 different ALK variants. RESULTS: Among 71 cases included in this study, FISH was evaluable in 58 cases. The concordance of ALK IHC with FISH was 75.9% and that with NGS was 84.5%. The sensitivities of FISH and NGS were 75.6% and 87.5%, respectively. The median progression-free survival of ALK IHC-positive and FISH-negative group was 5.5 months and that of both positive was 9.97 months. CONCLUSION: Although NGS offers a better throughput and visualisation, IHC still remains the quintessential screening tool in upfront diagnosis of ALK rearranged NSCLC.

Unusual Resistance Mechanisms in a Case of ROS 1-Rearranged NSCLC: A Case Report.

The unprecedented growth of the high-throughput next-generation sequencing has facilitated the identification of rare oncogene fusions such as ROS1 for NSCLC. ROS1 rearrangement has been observed in only 2% of cases of NSCLC and has been successfully targeted using various tyrosine kinase inhibitors including crizotinib. However, the on-target and off-target mechanisms of the resistance are still vague. Here, we report a case of a patient with ROS1 rearranged NSCLC presenting primary resistance to crizotinib.

Immunotherapy in advanced non-small-cell lung cancer (NSCLC) after progression on chemotherapy: real-world results from a prospective institutional cohort.

Objective: To analyze the outcomes of patients receiving immunotherapy (IO) with advanced non-driver mutated non-small-cell lung cancer (NSCLC) after progression on systemic treatment. Methods: The overall survival (OS), progression-free survival (PFS) and best response to IO of 64 patients who met our inclusion criteria were analyzed. Results: Median follow-up, OS and PFS were 35.9, 7.1 and 3.2 months, respectively. On uni- and multi-variable analysis, better ECOG PS and fewer extra-thoracic metastases were associated with prolonged OS and PFS. Response to IO was associated with prolonged OS, while thoracic radiotherapy and isolated CNS involvement were associated with prolonged PFS. ECOG PS, thoracic radiotherapy and PDL1 status significantly influenced the likelihood of response to IO. Overall, 30% patients experienced any grade toxicity. Conclusion: Our results are concordant with reported trial outcomes and support the application of IO in Indian patients.

Several clinical trials have demonstrated favorable results with immunotherapy in patients with lung cancer who do not have a mutation in their tumors. However, clinical trials are often designed to provide the best chance for a trial drug/intervention to demonstrate effectiveness. Therefore, they usually include relatively healthier patients compared to what clinicians see in their practice. To demonstrate the efficacy of a drug outside a clinical trial, a real-world analysis is performed, which is reported in this article. We analyzed lung cancer patients treated with immunotherapy at our institution and found comparable efficacy to reported clinical trials. This was important because the trials did not include any patients from our country. We also found that patients with fewer sites of involvement outside the lung and those who received radiotherapy to the lung (either during or before receiving immunotherapy) survived longer without disease progression.

Gene of the month: GTF2I.

The GTF2I is a general transcription factor and its mutations have been reported to be recurrent in thymic epithelial tumours and are rare in other malignancies. Apart from thymic epithelial tumours, these mutations have also been reported in a subgroup of T cell lymphomas, angioimmunoblastic T cell lymphomas. Soft tissue angiofibroma has been reported to harbour GTF2I-NCOA2 fusion, whereas GTF2I partners with Retinoic acid receptor alpha (RARA) in acute promyelocytic leukaemia as GTF2I-RARA GTF2I has also been implicated in immune disorders and two neuropsychiatric genetic disorders, namely autism and Williams-Beuren syndrome. The various structural, biochemical and functional properties of GTF2I suggest towards the oncogenic nature of this gene. Studies involving patients are presently few and the availability of biospecimens amenable to molecular diagnostic studies is limited. Future studies involving biospecimens and transformed cell lines shall provide a clear understanding of the GTF2I mechanistic to eventually lead to targeted treatment.

Non-amplification genetic alterations of HER2 gene in non-small cell lung carcinoma.

AIMS: The present study investigated the incidence and spectrum of human epidermal growth factor receptor 2 (HER2) mutations, associated clinicopathological characteristics and the co-occurrence of HER2 gene amplification in the HER2 gene mutated cases in non-small cell lung cancer (NSCLC). METHODS: All patients with advanced lung adenocarcinoma (LUAD) who underwent broad genomic profiling by next generation sequencing (NGS) from 2015 to 2019 were included in the study. HER2 gene amplification was checked in all the HER2 gene mutated cases. Tumour tissues of all the mutated cases were examined by fluorescent in situ hybridisation (FISH). RESULTS: Fifty-four (37.2%) out of the 145 cases harboured tier 1 driver mutations comprising EGFR in 22.1%, ALK rearrangements in 7.6% cases, ROS1 rearrangements and BRAF V600E in 3.5% cases each, and NTRK fusion in 0.7% cases. Nine (6.2%) cases exhibited a significant genetic alteration in HER2 gene (tiers 2 and 3) on NGS. The most common alteration was exon 20 insertion of amino acid sequence AYVM in five cases (p.E770_A771insAYVM) followed by insertion of YVMA (p.A771_Y772insYVMA) in one case, insGSP (p.V777_G778insGSP) in one case and two missense mutations: p.G776C and p.QA795C (novel variant). The median copy number of the HER2 gene was 3.21 while on FISH, the median HER2/CEP17 ratio was 2.0. CONCLUSIONS: There is a relatively higher occurrence of HER2 exon 20 mutations as primary oncogenic driver in NSCLC especially LUAD. Our cohort has demonstrated (p.E770_A771insAYVM) as the strikingly dominant insertion mutation against the most often globally reported (p.A771_Y772insYVMA).

Robust home brew fragment sizing assay for detection of MET exon 14 skipping mutation in non-small cell lung cancer patients in resource constrained community hospitals.

BACKGROUND: A mutation/deletion involving donor or acceptor sites for exon 14 results in splicing out of exon 14 of the mesenchymal epithelial transition (MET) gene and is known as "MET exon 14 skipping" (ΔMET14). The two recent approvals with substantial objective responses and improved progression-free survival to MET inhibitors namely capmatinib and tepotinib necessitate the identification of this alteration upfront. We herein describe our experience of ΔMET14 detection by an mRNA-based assay using polymerase chain reaction followed by fragment sizing. METHODS: This is a home brew assay which was developed with the concept that the transcripts from true ΔMET14 will be shorter by ~140 bases than their wild type counterparts. The cases which were called MET exon 14 skipping positive on next-generation sequencing (NGS) were subjected to this assay, along with 13 healthy controls in order to establish the validity for true negatives. RESULTS: Thirteen cases of ΔMET14 mutation were detected on NGS using RNA-based sequencing. Considering NGS as a gold standard, the sizing assay using both gel and capillary electrophoresis that showed 100% specificity for both with concordance rates of 84.6% and 88.2% with NGS, respectively, were obtained. CONCLUSIONS: Owing to the cost-effective nature and easy to use procedures, this assay will prove beneficial for small- and medium-sized laboratories where skilled technical personnel and NGS platforms are unavailable.

Clinicopathological aspects of V-Raf murine sarcoma viral oncogene homolog B1 (BRAF) mutated non-small cell lung carcinoma in an Indian cohort: is there a difference?

INTRODUCTION: Activating mutations in the BRAF gene have been reported in 0.8%-8% cases of NSCLC. Traditionally, diagnostics have mainly focused on detection of V600E and modalities like mutation specific IHC, allele specific real-time PCR have been utilized. This may underestimate true prevalence of the non-V600E variants. Broader panel NGS testing offers a one stop solution and may identify newer potentially targetable variants. This is a retrospective single center experience of patients with BRAF mutated NSCLC characterizing the molecular spectrum and clinicopathologic characteristics. METHODS: 260 patients underwent panel based NGS testing at our center, between 2017-2020. 13 BRAF mutant cases, were detected and were clinically reviewed. RESULTS: Thirteen cases of BRAF alterations were seen in out of 260 (5%) patients. Median age of the cohort was 62 years (range: 39-86 years) with a female predilection). Canonical BRAF V600E mutation was seen in 6 (46.2%) patients and 7 (53.8%) harbored a non-V600E alteration. Spectrum of non V600E alterations included G466E, G469A, N581I, V600_K601delins, D594G, L597Q, G649V and were commonly female (P>0.01) with a higher trend for liver metastases (P=0.09). Median PFS was 4.8 months on chemotherapy (P=0.8). All patients (13/13, 100%) were never smokers with an adenocarcinoma histology. CONCLUSION: This is a single center experience from an Indian NSCLC cohort and shows higher prevalence of non-V600E than V600E mutation reported in literature. This may be attributed to increased use of NGS testing revealing otherwise missed alterations on sequential single gene testing.

Malfeasance of KRAS mutations in carcinogenesis.

Activating mutations in the KRAS gene (Kirsten rat sarcoma 2 viral oncogene homolog gene) are commonly seen across the various solid organ and hematolymphoid neoplasms. With the likelihood of the mutation specific KRAS inhibitor entering clinical practice, the present studies profiled the landscape of these mutations in the Indian population to add to databases and posit the clinical utility of its emerging inhibitors. This study included 489 formalin fixed paraffin-embedded (FFPE) tissue samples from consecutive patients during a 5-year period (2015-2019). The clinical records were obtained from the medical record archives of the institution. Library preparation was done using the Oncomine Assay™. Sequencing was performed using the Ion PGM Hi-Q Sequencing Kit on the Ion Torrent Personal Genome Machine (Ion PGM) as well as on Ion Torrent S5 sequencer using the S5 sequencing kit. Ion Torrent Suite™ Browser version 5.10 and Ion Reporter™ version 5.10 were used for data analysis. A total of 50 cases with KRAS mutations were observed occurring most commonly in the codons 12 and 13. The G12D mutation was the most commonly encountered subtype in our cohort (21/50), whereas the G12C mutation was observed in 5 cases, and interestingly, this mutation was only seen in patients with non-small cell lung carcinoma (NSCLC). In the largest cohort from Indian subcontinent reporting spectrum of KRAS mutations in human cancers, an incidence of 11% was observed across all cancer types. Therapies targeting the G12C mutations can benefit up to 20% KRAS-mutated NSCLC. Building databases of spectrum of KRAS mutations in different populations across diverse cancer types is the anticipatory step to this end.