The Histopathology of BRAF-V600E–mutated Lung Adenocarcinoma

Molecular pathology of non-small cell carcinoma

Currently, lung cancer is treated by the highest number of therapeutic options and the benefits are based on multiple large-scale sequencing studies, translational research and new drug development, which has promoted our understanding of the molecular pathology of lung cancer. According to the driver alterations, different characteristics have been revealed, such as differences in ethnic prevalence, median age and alteration patterns. Consequently, beyond traditional chemoradiotherapy, molecular-targeted therapy and treatment with immune check-point inhibitors (ICI) also became available major therapeutic options. Interestingly, clinical results suggest that the recently established therapies target distinct lung cancer proportions, particularly between the EGFR/ALK and PD-1/PD-L1-positive subsets, e.g. the kinase inhibitors target driver mutation-positive tumours, whereas driver mutation-negative tumours respond to ICI treatment. These therapeutic efficacy-related differences might be explained by the molecular pathogenesis of lung cancer. Addictive driver mutations promote tumour formation with powerful transformation performance, resulting in a low tumour mutation burden, reduced immune surveillance, and subsequent poor response to ICIs. In contrast, regular tobacco smoke exposure repeatedly injures the proximal airway epithelium, leading to accumulated genetic alterations. In the latter pathway, overgrowth due to alteration and immunological exclusion against neoantigens is initially balanced. However, tumours could be generated from certain clones that outcompete immunological exclusion and outgrow the others. Consequently, this cancer type responds to immune check-point treatment. These pathogenic differences are explained well by the two-compartment model, focusing upon the anatomical and functional composition of distinct cellular components between the terminal respiratory unit and the air-conducting system.

Targeting molecular alterations in non-small-cell lung cancer: what's next?

In recent years, major advances have been achieved in our understanding of non-small-cell lung cancer (NSCLC) with oncogenic driver alterations and in the specific treatment of these with tyrosine kinase inhibitors. Currently, state-of-the-art management of patients with NSCLC (particularly adenocarcinoma or non-adenocarcinoma but with mild tobacco exposure) consists of the determination of EGFR, ALK, ROS1 and BRAF status, as they have US FDA and EMA approved targeted therapies. The increase in molecular knowledge of NSCLC and the development of drugs against other targets has settled new therapeutic indications. In this review we have incorporated the development around MET, KRAS and NTRK in the diagnosis of NSCLC given the therapeutic potential that they represent, as well as the drugs approved for these indications.

DNA Mismatch Repair-deficient Rectal Cancer Is Frequently Associated With Lynch Syndrome and With Poor Response to Neoadjuvant Therapy

We evaluated 368 consecutively resected rectal cancers with neoadjuvant therapy for DNA mismatch repair (MMR) protein status, tumor response to neoadjuvant therapy, histopathologic features, and patient survival. Nine (2.4%) rectal cancers were mismatch repair-deficient (MMRD): 8 (89%) Lynch syndrome-associated tumors and 1 (11%) sporadic MLH1-deficient tumor. Of the 9 MMRD rectal cancers, 89% (8/9) had a tumor regression score 3 (poor response) compared with 23% (81/359) of MMR proficient rectal cancers (P<0.001). Patients with MMRD rectal cancer less often had downstaging after neoadjuvant therapy compared with patients with MMR proficient rectal cancer (11% vs. 57%, P=0.007). In the multivariable logistic regression analysis, MMRD in rectal cancer was associated with a 25.11-fold increased risk of poor response to neoadjuvant therapy (tumor regression score 3) (95% confidence interval [CI]: 3.08-44.63, P=0.003). In the multivariable Cox regression analysis, the only variables significantly associated with disease-free survival were pathologic stage III disease (hazard ratio [HR]=2.46, 95% CI: 1.54-3.93, P<0.001), College of American Pathologists (CAP) tumor regression score 2 to 3 (HR=3.44, 95% CI: 1.76-6.73, P<0.001), and positive margins (HR=2.86, 95% CI: 1.56-5.25, P=0.001). In conclusion, we demonstrated that MMRD in rectal cancer is an independent predictor of poor response to neoadjuvant therapy and infrequently results in pathologic downstaging following neoadjuvant therapy. We also confirmed that MMRD in rectal cancer is strongly associated with a diagnosis of Lynch syndrome. Our results suggest that MMR status may help to provide a more patient-centered approach when selecting neoadjuvant treatment regimens and may help predict tumor response to neoadjuvant therapy.

Rapid screening using pathomorphological interpretation to detect BRAFV600E mutation and microsatellite instability in colorectal cancer

PURPOSE

Rapid decision-making is essential in precision medicine for initiating molecular targeted therapy for cancer patients. This study aimed to extract pathomorphological features that enable the accurate prediction of genetic abnormalities in cancer from hematoxylin and eosin (H&E) images using deep learning (DL).

EXPERIMENTAL DESIGN

A total of 1,657 images (one representative image per patient) of thin formalin-fixed, paraffin-embedded (FFPE) tissue sections from either primary or metastatic tumors with next-generation sequencing (NGS)-confirmed genetic abnormalities-including BRAFV600E and KRAS mutations, and microsatellite instability high (MSI-H)-that are directly relevant to therapeutic strategies for advanced colorectal cancer (CRC) were obtained from the nationwide SCRUM-Japan GI-SCREEN project. The images were divided into three groups of 986, 248, and 423 images to create one training and two validation cohorts, respectively. Pathomorphological feature-prediction DL models were first developed based on pathomorphological features. Subsequently, gene-prediction DL models were constructed for all possible combinations of pathomorphological features that enabled the predicting of gene abnormalities based on images filtered by the combination of pathomorphological feature-prediction models.

RESULTS

High accuracies were achieved, with areas under the curve (AUCs) &gt; 0.90 and 0.80 for 12 and 27, respectively, of 33 analyzed pathomorphological features, with high AUCs being yielded for both BRAFV600E (0.851 and 0.859) and MSI-H (0.923 and 0.862).

CONCLUSIONS

These findings show that novel next-generation pathology methods can predict genetic abnormalities without the need for standard-of-care gene tests and this novel next-generation pathology method can be applied for CRC treatment planning in the near future.

Selection Strategies and Practical Application of BRAF V600E-mutated Non-Small Cell Lung Carcinoma

Purpose

The incidence of BRAF V600E mutation in non–small cell lung carcinoma (NSCLC) is lower than 2%, which poses difficulties in finding legitimate patients for targeted therapy. We investigated the predictive factors pertaining to BRAF V600E and the effectiveness of the VE1 antibody as a screening method for patient selection.

Materials and Methods

The study was designed into two steps. In a first group, BRAF-mutated NSCLCs were identified from sequencing data to determine the features of BRAF V600E mutation. The results of the first group helped the collection of adenocarcinomas with a papillary or micropapillary pattern but without epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) alterations as a second group so that the frequency of BRAF V600E mutation could be calculated. The sensitivity and specificity of the VE1 were compared with BRAF V600E status.

Results

Among 39 BRAF-mutated NSCLCs in the first group, 20 (51%) were V600E. BRAF V600E mutation was more common in female patients and showed no significant correlation with smoking status. Nineteen cases were adenocarcinomas without EGFR and ALK alterations. The most common patterns of invasion were papillary and micropapillary along with central fibrosis. The sensitivity and specificity of the VE1 were 90.0% and 92.3%, respectively. In the second group, 6.7% of cases were VE1-positive, indicating that the prevalence was significantly higher than that reported in previous studies (0.3%–1.8%).

Conclusion

BRAF V600E-mutated NSCLCs could be enriched with the application of clinicopathologic parameters, which are not perfect. Therefore, additional VE1 immunohistochemistry may be useful as a screening method.

Advances in anti-BRAF therapies for lung cancer

Non-small cell lung cancer (NSCLC) is one of the most frequent causes of mortality in the western world. v-raf murine sarcoma viral oncogene homolog B (BRAF) is a member of the Raf kinase family and plays a critical role in cellular growth, proliferation, and differentiation through the mitogen-activated protein kinase pathway. The incidence of BRAF mutations in NSCLC is low, accounting for 0-3% of all cases of lung cancer. Given the results obtained in metastatic melanoma, several studies have reported the efficacy of anti-BRAF therapies in NSCLC treatment. In this review, we describe changes in the landscape of BRAF-mutated lung cancer treatment and analyze insights from major clinical trials in the context of future therapeutic prospects.

Automated Quantitation of CD8-positive T Cells Predicts Prognosis in Colonic Adenocarcinoma With Mucinous, Signet Ring Cell, or Medullary Differentiation Independent of Mismatch Repair Protein Status

Despite their association with DNA mismatch repair (MMR) protein deficiency, colonic adenocarcinomas with mucinous, signet ring cell, or medullary differentiation have not been associated with improved survival compared with conventional adenocarcinomas in most studies. Recent studies indicate that increased T-cell infiltration in the tumor microenvironment has a favorable prognostic effect in colonic adenocarcinoma. However, the prognostic effect of tumor-associated T cells has not been evaluated in histologic subtypes of colonic adenocarcinoma. We evaluated CD8-positive T-cell density in 259 patients with colonic adenocarcinoma, including 113 patients with tumors demonstrating mucinous, signet ring cell, or medullary differentiation, using a validated automated quantitative digital image analysis platform and correlated CD8-positive T-cell density with histopathologic variables, MMR status, molecular alterations, and survival. CD8-positive T-cell densities were significantly higher for MMR protein-deficient tumors (P<0.001), BRAF V600E mutant tumors (P=0.004), and tumors with medullary differentiation (P<0.001) but did not correlate with mucinous or signet ring cell histology (P>0.05 for both). In the multivariable model of factors predicting disease-free survival, increased CD8-positive T-cell density was associated with improved survival both in the entire cohort (hazard ratio=0.34, 95% confidence interval, 0.15-0.75, P=0.008) and in an analysis of patients with tumors with mucinous, signet ring cell, or medullary differentiation (hazard ratio=0.06, 95% confidence interval, 0.01-0.54, P=0.01). The prognostic effect of CD8-positive T-cell density was independent of tumor stage, MMR status, KRAS mutation, and BRAF mutation. Venous invasion was the only other variable independently associated with survival in both the entire cohort and in patients with tumors with mucinous, signet ring cell, or medullary differentiation. In summary, our results indicate that the prognostic value of MMR protein deficiency is most likely attributed to increased tumor-associated CD8-positive T cells and that automated quantitative CD8 T-cell analysis is a better biomarker of patient survival, particularly in patients with tumors demonstrating mucinous, signet ring cell, or medullary differentiation.

[Updated guidelines for predictive biomarker testing in advanced non-small-cell lung cancer: A National Consensus of the Spanish Society of Pathology and the Spanish Society of Medical Oncology]

In 2011, the Spanish Society of Medical Oncology (SEOM) and the Spanish Society of Pathology (SEAP) initiated a joint project to establish guidelines for biomarker testing in patients with advanced non-small-cell lung cancer based on the information available at the time. As this field is constantly evolving, these guidelines were updated in 2012 and 2015 and now in 2019. Current evidence suggests it should be mandatory to test all patients with this kind of advanced lung cancer for EGFR and BRAF mutations, ALK and ROS1 rearrangements and PD-L1 expression. The growing need to study other emerging biomarkers has promoted the routine use of massive sequencing (next-generation sequencing, NGS). However, the coordination of every professional involved and the prioritisation of the most suitable tests and technologies for each case remain a challenge.

Clinical Characteristics and Treatment Outcomes of 65 Patients With BRAF-Mutated Non-small Cell Lung Cancer

BRAF mutation is an oncogenic driver gene in non-small cell lung cancer (NSCLC) with low frequency. The data of patients with NSCLC harboring BRAF mutations is rare. We conducted a retrospective multicenter study in Chinese patients with NSCLC harboring BRAF mutations between Jan 2017 and Jul 2019. A total of 65 patients treated in 22 centers were included, 54 harbored BRAF-V600E mutation and 11 had non-V600E mutations, including K601E, G469S, G469V, G469A, G596R, G466R, and T599dup. Of 18 patients with early-stage disease at diagnosis and underwent a resection, the median disease-free survival (DFS) was 43.2, 18.7, and 10.1 months of stage I, II, and IIIA patients, respectively. In 46 patients with advanced-stage disease at data cutoff, disease control rate (DCR), and progression-free survival (PFS) of first-line anti-BRAF targeted therapy was superior than chemotherapy in patients harboring BRAF-V600E mutation (DCR, 100.0 vs. 70.0%, P = 0.027; median PFS, 9.8 vs. 5.4 months, P = 0.149). Of 30 V600E-mutated patients who received anti-BRAF therapy during the course of disease, median PFS of vemurafenib, dabrafenib, and dabrafenib plus trametinib was 7.8, 5.8, and 6.0 months, respectively (P = 0.970). Median PFS were similar between V600E and non-V600E patients (5.4 vs. 5.4 months, P = 0.825) to first-line chemotherapy. Nine patients were treated with checkpoint inhibitors, with median PFS of 3.0 months. Our data demonstrated the clinical benefit of anti-BRAF targeted therapy in Chinese NSCLC patients harboring BRAF-V600E mutation. The value of immunotherapy and treatment selection among non-V600E population needs further study.

Switch/sucrose nonfermenting nucleosome complex-deficient colorectal carcinomas have distinct clinicopathologic features

The switch/sucrose nonfermenting (SWI/SNF) nucleosome complex consists of several proteins that are involved in cellular proliferation and tumor suppression. The aim of this study was to correlate immunohistochemical expression of four SWI/SNF complex subunits, SMARCA2, SMARCB1, SMARCA4, and ARID1A, with clinicopathologic and molecular features and patient survival in 338 patients with colorectal adenocarcinoma using a tissue microarray approach. Twenty-three (7%) colorectal adenocarcinomas demonstrated deficient SWI/SNF expression: 7 had SMARCA2 deficiency, 12 had ARID1A deficiency, and 4 had both SMARCA2 and ARID1A deficiency. No cases were SMARCB1 or SMARCA4 deficient. Twelve (52%) SWI/SNF complex-deficient tumors demonstrated mismatch repair (MMR) deficiency (p = 0.02), 6 (26%) showed medullary differentiation (p = 0.001), and 9 were negative for CDX2 expression (p < 0.001). Among the MMR-deficient SWI/SNF complex-deficient tumors, 8 were sporadic MLH1 deficient, and 4 were seen in patients with Lynch syndrome. Compared with tumors with ARID1A deficiency alone, SMARCA2-deficient tumors were less likely to exhibit MMR deficiency (27% vs. 75%, p = 0.04), medullary differentiation (0% vs. 50%, p = 0.01), and mucinous differentiation (0% vs. 42%, p = 0.04). Conventional gland-forming histology was more often identified in SMARCA2-deficient tumors (11/11, 100%) than in tumors with ARID1A deficiency alone (4/12, 33%) (p = 0.001). There was no difference in KRAS mutation, BRAF mutation, stage, disease-specific survival, or disease-free survival for patients stratified by SWI/SNF expression (all with p > 0.05). In conclusion, SMARCA2-deficient and ARID1A-deficient colorectal carcinomas had distinctly different clinicopathologic features, with ARID1A-deficient tumors exhibiting medullary and mucinous differentiation and MMR deficiency and SMARCA2-deficient tumors demonstrating conventional gland-forming histologic growth with less frequent MMR deficiency.

Immunohistochemical Study Using Monoclonal VE1 Antibody Can Substitute the Molecular Tests for Apprehension of BRAF V600E Mutation in Patients with Non-small-Cell Lung Carcinoma

In patients with non-small-cell lung carcinoma (NSCLC), the analysis of BRAF V600E mutation has become more and more applied since the introduction of many mutation-targeted medications. In this regard, the advantage of immunohistochemistry (IHC) as a reliable diagnostic test substitute to other molecular studies has not been approved yet. Objective. To examine the dependability of using immunohistochemical method utilizing monoclonal VE1 antibody in the detection of BRAF V600 E mutation in patients with non-small-cell lung carcinoma and compare the results there with that of polymerase chain reaction (SSCP-PCR). Materials and Methods. We retrospectively identified 53 patients of whom their histopathological diagnosis was non-small-cell carcinoma of different types. Evaluation of BRAF V600E mutation was assessed using polymerase chain reaction (SSCP-PCR) and IHC using VE1 antibody. This approach was applied to all cases under the study. Results. Among the 53 NSCLC samples, only 5 (9.3%) cases harbored BRAF V600E mutation, 80% were of adenocarcinoma type, and the rest (20%) was of squamous cell carcinoma. IHC analysis for VE1 was positive in 4 out of 5 (80%) BRAF-mutated tumors and negative in all nonmutated BRAF V600 E NSCLC. Conclusion. Our results revealed that VE1 antibody IHC analysis is a promising technique that can be used to detect BRAF V600-mutated NSCLC with relatively high specificity and sensitivity and might become a potential alternative to the current molecular biological methods that are in use for this purpose.

Updated guidelines for predictive biomarker testing in advanced non-small-cell lung cancer: a National Consensus of the Spanish Society of Pathology and the Spanish Society of Medical Oncology

In 2011 the Spanish Society of Medical Oncology (SEOM) and the Spanish Society of Pathology (SEAP) started a joint project to establish guidelines on biomarker testing in patients with advanced non-small-cell lung cancer (NSCLC) based on current evidence. As this field is constantly evolving, these guidelines have been updated, previously in 2012 and 2015 and now in 2019. Current evidence suggests that the mandatory tests to conduct in all patients with advanced NSCLC are for EGFR and BRAF mutations, ALK and ROS1 rearrangements and PD-L1 expression. The growing need to study other emerging biomarkers has promoted the routine use of massive sequencing (next-generation sequencing, NGS). The coordination of every professional involved and the prioritisation of the most suitable tests and technologies for each case remains a challenge.

SATB2 and CDX2 are prognostic biomarkers in DNA mismatch repair protein deficient colon cancer

DNA mismatch repair protein deficient colon cancer frequently displays reduced CDX2 expression, and recent literature has suggested that negative CDX2 expression is a poor prognostic biomarker in colon cancer. We have recently demonstrated that SATB2 is an immunohistochemical marker that is complementary to CDX2. Using a tissue microarray approach, we evaluated SATB2 and CDX2 immunohistochemical expression in 514 patients with colonic adenocarcinoma including 146 with mismatch repair protein deficient tumors and correlated expression with histopathologic variables, molecular alterations, and survival. Overall, SATB2-negative and/or CDX2-negative expression was identified in 33% of mismatch repair protein deficient tumors compared with only 15% of mismatch repair protein proficient tumors (p < 0.001) and in 36% of BRAF V600E mutated compared with only 13% of BRAF wild-type tumors (p < 0.001). Both SATB2-negative and CDX2-negative colonic adenocarcinomas more often displayed lymphatic invasion, venous invasion, and perineural invasion (all with p < 0.05). SATB2-negative expression was also more frequently identified in tumors with mucinous or signet ring cell differentiation (p < 0.01 for both). In a multivariable analysis of survival in patients with mismatch repair protein deficient tumors (n = 131), only tumor stage (p = 0.01) and SATB2-negative and/or CDX2-negative expression (p = 0.009) independently predicted disease-specific survival. Of the 99 patients with stage II or III mismatch repair protein deficient tumors, death from disease only occurred in patients with either SATB2-negative or CDX2-negative tumors, and no patients with SATB2-positive/CDX2-positive tumors developed recurrence or died of disease. SATB2 and CDX2 expression had no effect on patient survival in mismatch repair protein proficient, BRAF-mutated, or KRAS-mutated tumors. In summary, our results suggest that SATB2 and CDX2 are prognostic biomarkers in patients with mismatch repair protein deficient colon cancer and that inclusion of SATB2 and CDX2 immunohistochemistry may be helpful as part of a comprehensive pathologic risk assessment in mismatch repair protein deficient colon cancer.

Validation of Immunohistochemistry for the Detection of BRAF V600E-Mutated Lung Adenocarcinomas

BRAF V600E mutation, a missense mutation in exon 15 resulting in valine substitution for glutamate at position 600 within the kinase domain of BRAF oncogene, is found in a subset of lung adenocarcinoma (ADC). The usefulness of immunohistochemistry (IHC) as an alternative diagnostic tool has not been validated. Moreover, the clinical information of patients with BRAF V600E-mutated lung ADC is limited. We retrospectively identified 31 lung ADCs diagnosed with BRAF V600E mutation by standard molecular sequencing methods and reviewed their clinical characteristics and pathological features. An anti-BRAF V600E monoclonal VE1 antibody for IHC was used to confirm the expression patterns. The series was comprised of 99 cases, 29 with BRAF V600E mutation and 70 without BRAF V600E but with other types or undetected mutations. The majority of BRAF V600E-mutated biopsied tissues were poorly differentiated and micropapillary patterns. Application of the IHC VE1 assay was highly feasible in primary/metastatic sites or effusion blocks, yielding positive findings in 28 of 29 (96.6%) BRAF V600E-mutated tumors and negative results in 69 of 70 (98.6%) tumors harboring other types or undetected mutations. Patients who received pemetrexed/platinum-based rather than mutation-targeted chemotherapy as the first-line therapy for metastatic disease showed median overall survival of 15.5 months. Our findings indicated that VE1 antibody-based IHC analysis demonstrated high sensitivity and specificity to detect BRAF V600E-mutated lung ADCs in tissues from primary or metastatic sites.

Site-specific Differences in Colonic Adenocarcinoma: KRAS Mutations and High Tumor Budding Are More Frequent in Cecal Adenocarcinoma

Recent literature indicates that adenocarcinomas of the cecum differ with respect to molecular alterations compared with noncecal proximal colon adenocarcinomas and that cecal tumor site may be a prognostically relevant variable. We compared molecular alterations, histopathologic features, and disease-specific survival in a series of 328 colonic adenocarcinomas identified over a 2-year period and stratified by tumor location (cecum, right colon, and left colon). Overall, cecal adenocarcinomas demonstrated the highest frequency of molecular abnormalities with 74% harboring either a KRAS exon 2 or 3 mutation, a BRAF mutation, or DNA mismatch repair protein deficiency. KRAS mutations were more frequently seen in the cecum compared with all other tumor sites (P=0.03). KRAS mutations were identified in 46% of cecal adenocarcinomas compared with only 25% of adenocarcinomas of the right colon (P=0.004). Cecal adenocarcinomas more frequently displayed adverse histopathologic features, in particular high tumor budding (31%), compared with tumors of the right colon (18%; P=0.04) and tumors of the left colon (17%; P=0.02). Overall stage was the most important independent predictor of disease-specific survival in the multivariable analysis; however, cecal tumor site and high tumor budding were also predictive of poor survival, particularly in patients with stage III or IV tumors. In conclusion, cecal adenocarcinomas are characterized by a high frequency of KRAS mutations compared with noncecal right colon tumors, frequently display high tumor budding, and may be a prognostically relevant variable, particularly in patients with stage III or IV disease.

Natural Disease History, Outcomes, and Co-mutations in a Series of Patients With BRAF-Mutated Non-small-cell Lung Cancer

BACKGROUND

BRAF mutations occur in 1% to 4% of non-small-cell lung cancer (NSCLC) cases. Previous retrospective studies have reported similar outcomes for BRAF-mutated NSCLC as compared with wild-type tumors without a known driver mutation or tumors harboring other mutations. However, select cases of prolonged survival have also been described, and thus, the natural history of BRAF-mutated NSCLC remains an area of ongoing study. The aim of this series was to describe the natural history, clinical outcomes, and occurrence of co-mutations in patients with BRAF-mutated NSCLC.

PATIENTS AND METHODS

Patients with BRAF-mutated NSCLC seen at Stanford University Medical Center from January 1, 2006 through July 31, 2015 were reviewed. The Kaplan-Meier method was used to calculate median overall survival, and the generalized Wilcoxon test was used to compare median survivals across subgroups of patients.

RESULTS

Within a cohort of 18 patients with BRAF-mutated NSCLC, V600E mutations were most common (72%; 13/18). Clinicopathologic features were similar between patients with V600E versus non-V600E mutations, although there was a trend toward more patients with non-V600E mutations being heavy smokers (80% vs. 31%; P = .12). Co-occurring mutations in TP53 were identified most commonly (28%; 5/18). The median overall survival for the entire cohort was 40.1 months, and the median survival from the onset of metastases (n = 16) was 28.1 months. Survival rates at 2 and 5 years from the onset of metastases were 56% and 13%, respectively.

CONCLUSION

The clinical behavior of BRAF-mutated NSCLC is variable, but favorable outcomes can be seen in a subset of patients.

DNA mismatch repair protein deficient non-neoplastic colonic crypts: a novel indicator of Lynch syndrome

Lynch syndrome is the most common form of hereditary colorectal carcinoma. However, establishing the diagnosis of Lynch syndrome is challenging, and ancillary studies that distinguish between sporadic DNA mismatch repair (MMR) protein deficiency and Lynch syndrome are needed, particularly when germline mutation studies are inconclusive. The aim of this study was to determine if MMR protein-deficient non-neoplastic intestinal crypts can help distinguish between patients with and without Lynch syndrome. We evaluated the expression of MMR proteins in non-neoplastic intestinal mucosa obtained from colorectal surgical resection specimens from patients with Lynch syndrome-associated colorectal carcinoma (n = 52) and patients with colorectal carcinoma without evidence of Lynch syndrome (n = 70), including sporadic MMR protein-deficient colorectal carcinoma (n = 30), MMR protein proficient colorectal carcinoma (n = 30), and "Lynch-like" syndrome (n = 10). MMR protein-deficient non-neoplastic colonic crypts were identified in 19 of 122 (16%) patients. MMR protein-deficient colonic crypts were identified in 18 of 52 (35%) patients with Lynch syndrome compared to only 1 of 70 (1%) patients without Lynch syndrome (p < 0.001). This one patient had "Lynch-like" syndrome and harbored two MSH2-deficient non-neoplastic colonic crypts. MMR protein-deficient non-neoplastic colonic crypts were not identified in patients with sporadic MMR protein-deficient or MMR protein proficient colorectal carcinoma. Our findings suggest that MMR protein-deficient colonic crypts are a novel indicator of Lynch syndrome, and evaluation for MMR protein-deficient crypts may be a helpful addition to Lynch syndrome diagnostics.

Detection of RAS and RAS-associated alterations in primary lung adenocarcinomas. A correlation between molecular findings and tumor characteristics

Rat sarcoma (RAS) and RAS-associated pathways play important roles in the pathogenesis of lung cancers and in the development of targeted therapies. However, the clinical significance of RAS pathways is still not fully understood. We investigated the RAS-associated molecular aberrations in primary lung adenocarcinomas and correlated molecular findings with clinicopathological characteristics of tumors. A total of 220 surgically resected tumors were identified for which a lung cancer molecular panel (testing 7 genes by next-generation sequencing and 3 genes for rearrangement by fluorescence in situ hybridization) had been performed. The overall molecular alterations were detected in 143 cases (65.00%), including 58 cases (26.36%) of KRAS, 40 cases (18.18%) of EGFR, 24 cases (10.91%) of BRAF, 8 cases (3.64%) of PIK3CA, 7 cases (3.18%) of NRAS, 6 cases (2.73%) of ALK alterations. KRAS, BRAF, NRAS, and PIK3CA mutations were more commonly seen in smokers and occurred with much higher rates than previously published data. BRAF^V600E mutations were commonly seen in female smokers, whereas, BRAF^non-V600E mutations were seen in both male and female smokers with moderately to poorly differentiated tumors. PIK3CA mutations were predominantly occurred in p.E545K and p.E542K on exon 9 in moderately to poorly differentiated tumors.

Histopathological Predictors of Recurrence in Stage III Colon Cancer: Reappraisal of Tumor Deposits and Tumor Budding Using AJCC8 Criteria

Patients with stage III colonic adenocarcinoma have a spectrum of risk for recurrent disease, and histopathological variables that predict recurrence can help stratify patients into prognostic groups. To identify histopathological predictors of recurrence, we investigated the effect of implementation of the eighth edition of the American Joint Committee on Cancer (AJCC8) staging system definition of tumor deposits and International Tumor Budding Consensus Conference (ITBCC) criteria for tumor budding compared with other known prognostic variables in 256 resected colonic adenocarcinomas, including 150 stage III and 106 stage II tumors. In stage III colon cancer, tumor deposits and high tumor budding were the only independent histological variables that predicted disease recurrence. In a multivariable analysis in stage III colon cancer, tumor deposits and high tumor budding were associated with a 2.2- and 1.5-fold increased risk of developing disease recurrence, respectively (95% CI = 1.1-4,2, P = .02, and 95% CI = 1.1-2.1, P = .01, respectively). The negative prognostic effect of tumor deposits was most pronounced in patients with stage IIIB disease in which tumor deposits were associated with a 3.2-fold increased risk of disease recurrence (95% CI = 1.4-7.1; P = .005). Within the N1 cohort, patients with tumor deposits without concurrent positive lymph nodes (N1c) had a significantly decreased disease-free survival compared with patients with N0 tumors ( P < .001) and patients with N1a/b tumors ( P = .02). As independent risk factors for recurrence, tumor deposits and high tumor budding are important histopathological variables and should be included as a part of a routine comprehensive pathological risk assessment in stage III colon cancer.

BRAF in non-small cell lung cancer (NSCLC): Pickaxing another brick in the wall

Molecular characterization of non-small cell lung cancer (NSCLC) marked an historical turning point for the treatment of lung tumors harboring kinase alterations suitable for specific targeted drugs inhibition, translating into major clinical improvements. Besides EGFR, ALK and ROS1, BRAF represents a novel therapeutic target for the treatment of advanced NSCLC. BRAF mutations, found in 1.5-3.5% of NSCLC, are responsible of the constitutive activation of mitogen activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway. Clinical trials evaluating the efficacy of the BRAF inhibitor dabrafenib in combination with the downstream MEK inhibitor trametinib in metastatic BRAF^V600E-mutated NSCLC guaranteed FDA and EMA rapid approval of the combination regimen in this clinical setting. In line with the striking results observed in metastatic melanoma harboring the same molecular alteration, BRAF and MEK inhibition should be considered a new standard of care in this molecular subtype of NSCLC. In the present review, we propose an overview of the available evidence about BRAF in NSCLC mutations (V600E and non-V600E), from biological significance to emerging clinical implications of BRAF mutations detection. Focusing on the current strategies to act against the mutated kinase, we moreover approach additional strategies to overcome treatment resistance.

Erdheim-Chester disease: description of two illustrative cases involving the lung

AIM

Erdheim-Chester disease represents a clonal systemic proliferation of histiocytes. Bone is the most common site of involvement, although almost any organ, including the lungs, can be affected.

METHODS AND RESULTS

The diagnosis of Erdheim-Chester disease can be difficult, owing to its rarity and protean presentation. Correlation between clinical, radiological and histological findings is mandatory for identification of the disease. Foamy histiocytes, lacking Langerhans cell markers, represent the typical histological findings, although their absence does not rule out Erdheim-Chester disease. Identification of BRAF mutation can be helpful in making the diagnosis, and allows for the development and application of targeted therapies in this setting.

CONCLUSIONS

Herein, we describe two cases presenting with lung involvement and vertebral lesions, lacking the more typical long-bone involvement. One case histologically mimicked Rosai-Dorfman disease. However, both cases harboured the pathognomonic BRAFV600E mutation.

Mucinous and Signet Ring Cell Differentiation Affect Patterns of Metastasis in Colorectal Carcinoma and Influence Survival

Peritoneal metastasis in colorectal carcinoma is associated with a dismal prognosis; however, features that correlate with patterns of metastatic spread are not well characterized. We analyzed the clinicopathologic and molecular features of 166 patients with colorectal carcinomas stratified by metastases to the peritoneum or liver. Mucinous and signet ring cell differentiation were more frequently observed in colorectal carcinoma with peritoneal dissemination compared to colorectal carcinoma with liver metastasis (mucinous differentiation: 62% vs 23%, P < .001; signet ring cell differentiation: 21% vs 0%, P < .0001). The significant association of mucinous differentiation with peritoneal dissemination compared with liver metastasis was identified in patients with both synchronous and metachronous development of metastasis ( P < .01). In contrast, colorectal carcinomas with liver metastasis were more frequently low-grade (90% vs 72%, P = .005) and associated with dirty necrosis (81% vs 56%, P = .001) compared with colorectal carcinomas with peritoneal dissemination. No significant differences were identified between colorectal carcinoma with peritoneal metastasis versus liver metastasis with respect to KRAS mutations, BRAF mutation, or high levels of microsatellite instability. Patients with tumors involving the peritoneum had a significantly worse overall survival in comparison to patients with liver metastasis lacking peritoneal involvement ( P = .02). When including only those patients with peritoneal metastasis, the presence of any mucinous or signet ring cell differentiation was associated with a significantly worse overall survival ( P = .006). Our findings indicate that mucinous and signet ring cell differentiation may be histologic features that are associated with an increased risk of peritoneal dissemination and poor overall survival in patients with peritoneal metastasis.

Correlation of Histologic Subtypes and Molecular Alterations in Pulmonary Adenocarcinoma: Therapeutic and Prognostic Implications

Major driver mutations of pulmonary adenocarcinomas have been identified and highlighted as actionable targets for precision cancer medicine. As phenotype is largely determined by genotype, genetic changes associated with morphologic features have recently received more attention from both pathologists and clinicians. The morphologic features of adenocarcinomas with mutations in EGFR or KRAS, or translocated ALK, have rarely been described. Pulmonary adenocarcinomas with EGFR mutations, the most common driver mutation encountered in Asian patients with pulmonary adenocarcinoma, show lepidic or papillary organotypic growth patterns. KRAS-mutated adenocarcinomas demonstrate nonorganotypic growth patterns, especially mucin-containing cells. P53 mutations are associated with aggressiveness rather than growth patterns. HER2 mutations are observed in mucinous adenocarcinoma and adenocarcinoma with micropapillary features. The histologic features of BRAF-mutated adenocarcinomas have not yet been established, but papillary, lepidic, solid, and acinar patterns have been observed. Adenocarcinomas with rearrangement of ALK, ROS1, and RET genes share similar histologic features, such as solid signet-ring cells and cribriform formation. However, adenocarcinomas with NRG1 rearrangements frequently show mucinous morphology. The histologic features and related mutations of adenocarcinomas with expression of programmed cell death-1 and programmed cell death ligands-1 may be helpful in guiding immunotherapeutic treatment. This review describes histopathologic features of adenocarcinomas and their correlation with molecular alterations.

Colorectal poorly differentiated neuroendocrine carcinomas frequently exhibit BRAF mutations and are associated with poor overall survival

The molecular alterations in colorectal poorly differentiated neuroendocrine carcinoma remain incompletely characterized, particularly with respect to mutations in BRAF and KRAS. We analyzed 32 colorectal poorly differentiated neuroendocrine carcinomas and 40 colorectal poorly differentiated conventional adenocarcinomas for mutations in KRAS and BRAF and for DNA mismatch repair protein abnormalities to correlate histopathology with molecular alterations and survival. Compared with poorly differentiated conventional adenocarcinoma, poorly differentiated neuroendocrine carcinoma frequently harbored BRAF mutations (59% versus 5%; P < .001) and less frequently demonstrated KRAS codon 12 or 13 mutations (17% versus 43%; P = .03). BRAF mutations were identified in both pure poorly differentiated neuroendocrine carcinoma (60%) and poorly differentiated neuroendocrine carcinoma associated with a signet ring cell adenocarcinoma component (82%). Most (93%) poorly differentiated neuroendocrine carcinomas demonstrated proficient DNA mismatch repair by either microsatellite instability polymerase chain reaction or DNA mismatch repair immunohistochemistry. Patients with poorly differentiated neuroendocrine carcinoma had a significantly worse overall survival compared with patients with poorly differentiated conventional adenocarcinoma (P < .001). There was no significant difference in overall survival between patients with pure poorly differentiated neuroendocrine carcinoma and patients with both poorly differentiated neuroendocrine carcinoma and adenocarcinoma components (P = .5). In conclusion, colorectal poorly differentiated neuroendocrine carcinomas frequently harbor BRAF mutations and are associated with poor overall survival.

M, Mills GB, Heymach JV, Wistuba II, Wang J, Byers. LA. An Integrated Molecular Analysis of Lung Adenocarcinomas Identifies Potential Therapeutic Targets among TTF1-Negative Tumors, Including DNA Repair Proteins and Nrf2

PURPOSE

Thyroid transcription factor-1 (TTF1) immunohistochemistry (IHC) is used clinically to differentiate primary lung adenocarcinomas (LUAD) from squamous lung cancers and metastatic adenocarcinomas from other primary sites. However, a subset of LUAD (15%-20%) does not express TTF1, and TTF1-negative patients have worse clinical outcomes. As there are no established targeted agents with activity in TTF1-negative LUAD, we performed an integrated molecular analysis to identify potential therapeutic targets.

EXPERIMENTAL DESIGN

Using two clinical LUAD cohorts (274 tumors), one from our institution (PROSPECT) and The Cancer Genome Atlas, we interrogated proteomic profiles (by reverse phase protein array, RPPA), gene expression, and mutational data. Drug response data from 74 cell lines were used to validate potential therapeutic agents.

RESULTS

Strong correlations were observed between TTF1 IHC and TTF1 measurements by RPPA (Rho = 0.57, P < 0.001) and gene expression (NKX2-1, Rho = 0.61, P < 0.001). Established driver mutations (e.g., BRAF and EGFR) were associated with high TTF1 expression. In contrast, TTF1-negative LUAD had a higher frequency of inactivating KEAP1 mutations (P = 0.001). Proteomic profiling identified increased expression of DNA repair proteins (e.g., Chk1 and the DNA repair score) and suppressed PI3k/mTOR signaling among TTF1-negative tumors, with differences in total proteins confirmed at the mRNA level. Cell line analysis showed drugs targeting DNA repair to be more active in TTF1-low cell lines.

CONCLUSIONS

Combined genomic and proteomic analyses demonstrated infrequent alteration of validated lung cancer targets (including the absence of BRAF mutations in TTF1-negative LUAD), but identified novel potential targets for TTF1-negative LUAD, including KEAP1/Nrf2 and DNA repair pathways.

Clinicopathological comparison of colorectal and endometrial carcinomas in patients with Lynch-like syndrome versus patients with Lynch syndrome

Screening for DNA mismatch repair (MMR) deficiency in colorectal and endometrial carcinomas identifies patients at risk for Lynch syndrome. Some patients with MMR-deficient tumors have no evidence of a germline mutation and have been described as having Lynch-like syndrome. We compared the clinicopathological features of colorectal and endometrial carcinomas in patients with Lynch-like syndrome and Lynch syndrome. Universal screening identified 356 (10.6%) of 3352 patients with colorectal carcinoma and 72 (33%) of 215 patients with endometrial carcinoma with deficient DNA MMR. Sixty-six patients underwent germline mutation analysis with 45 patients (68%) having evidence of a germline MMR gene mutation confirming Lynch syndrome and 21 patients (32%) having Lynch-like syndrome with no evidence of a germline mutation. Most patients with Lynch-like syndrome had carcinoma involving the right colon compared to patients with Lynch syndrome (93% versus 45%; P < .002). All patients with colorectal carcinomas demonstrating isolated loss of MSH6 expression had Lynch syndrome confirmed by germline mutation analysis. Synchronous or metachronous Lynch syndrome-associated carcinoma was more frequently identified in patients with Lynch syndrome compared to Lynch-like syndrome (38% versus 7%; P = .04). There were no significant differences in clinicopathological variables between patients with Lynch-like syndrome and Lynch syndrome with endometrial carcinoma. In summary, 32% of patients with MMR deficiency concerning Lynch syndrome will have Lynch-like syndrome. Our results demonstrate that patients with Lynch-like syndrome are more likely to have right-sided colorectal carcinoma, less likely to have synchronous or metachronous Lynch syndrome-associated carcinoma, and less likely to demonstrate isolated loss of MSH6 expression within their tumor.

Prevalence and clinical significance of BRAF V600E in Chinese patients with lung adenocarcinoma

Background

The purpose of this study was to investigate the prevalence, distribution, and prognostic role of v-raf murine sarcoma viral oncogene homolog B (BRAF) V600E mutations in Chinese patients with lung adenocarcinoma (ADC), and to explore the possibility of BRAF V600E mutation detection in plasma DNA.

Methods

Data from 190 patients with lung ADCs treated at the Peking University Cancer Hospital from July 2011 to March 2012 were collected. The amplification refractory mutation system was used for BRAF V600E testing and denaturing high-performance liquid chromatography for epidermal growth factor receptor (EGFR) mutation detection. In BRAF V600E-mutant cases, paired plasma DNA was tested for mutation status of BRAF V600E and EGFR. The distribution and prognostic role of BRAF V600E mutations were analyzed using SPSS 13.0.

Results

Among 190 patients with advanced lung ADC, eight (4.2%) cases carried BRAF V600E mutations. V600E mutations presented more frequently in women than in men (6 of 96, 6.3% vs. P = 0.1). BRAF and EGFR mutations were concomitantly presented in three patients. Five of the eight patients with BRAF V600E mutations had matched plasma DNA samples and V600E mutations were found in three plasma samples.

Conclusion

The prevalence of BRAF V600E mutations in Chinese patients with lung ADC is 4.2%. Circulating plasma DNA may be used for BRAF V600E mutation analysis in lung adenocarcinoma.

BRAF V600E mutations: a series of case reports in patients with non-small cell lung cancer

We present a series of five patients with BRAF-mutated non-small cell lung cancer (NSCLC) from the Moffitt Cancer Center and a brief literature review. Information utilized included outside medical records, imaging studies, pathology reports in which simultaneous mutation testing was performed, and clinic visit notes. In addition, we conducted a literature search of background information using the following search terms: "BRAF mutations", "non-small cell lung cancer", and "driver mutations". Several retrospective studies on BRAF mutations in patients with NSCLC found that the majority of these mutations occur in adenocarcinomas and are V600E mutations. From our patients and literature search, we found that BRAF-V600E mutations occur predominantly in female smokers with adenocarcinomas.

Republished: lung cancer in never-smokers. Does smoking history matter in the era of molecular diagnostics and targeted therapy?

Lung cancer in never-smokers was recognised as a distinct clinical entity around the mid-2000s because these patients tended to be Asian women and diagnosed at a younger age with a preponderance of adenocarcinoma and better survival outcome despite a more advanced stage of presentation. It was soon discovered that lung cancer in never-smokers had a higher prevalence of activating EGFR mutations and we tend to classify lung cancer by smoking status for screening purpose. With the discoveries of many actionable driver mutations such as activating EGFR mutations and ALK rearrangement in adenocarcinoma of the lung we have switched to classifying non-small cell lung cancer into different individual molecular subgroups based on the presence of a dominant driver mutation. Although many actionable driver mutations are found in never-smokers with adenocarcinoma, this review will summarise that a substantial proportion of patients with these actionable driver mutations had a previous smoking history. Alternatively among the driver mutations that are associated with smoking history, a fair amount of these patients were never-smokers. Thus smoking status should not be used as a screen strategy for identifying driver mutations in clinical practice. Finally smoking history may have predictive and/or prognostic significance within individual molecular subgroups and identifying the difference according to smoking history may help optimise future targeted therapy.

Isocitrate dehydrogenase-1 is mutated in inflammatory bowel disease-associated intestinal adenocarcinoma with low-grade tubuloglandular histology but not in sporadic intestinal adenocarcinoma

The underlying molecular alterations in chronic idiopathic inflammatory bowel disease-associated intestinal adenocarcinoma remain largely unknown. Somatic IDH mutations are often seen in gliomas and myeloid leukemia but have also been recently reported in a subset of other neoplasms. We analyzed a series of intestinal adenocarcinomas with (n=23) and without (n=39) associated chronic idiopathic inflammatory bowel disease treated at our institution for IDH1 and IDH2 mutations and correlated the clinicopathologic findings with mutation status. Compared with intestinal adenocarcinomas not associated with inflammatory bowel disease, adenocarcinomas associated with inflammatory bowel disease more frequently demonstrated IDH mutations (13% vs. 0%, P=0.047). All IDH mutations were identified in IDH1 and resulted in substitution of arginine by cysteine at position 132 (p.R132C, c.394C>T). IDH1 mutations were frequently (66%) associated with concurrent KRAS mutations (p.G12D, c.35G>A). IDH1-mutated intestinal adenocarcinomas were seen in the setting of both Crohn disease and ulcerative colitis and were located in both the ileum and colon. Compared with IDH1-negative inflammatory bowel disease-associated adenocarcinoma, IDH1-positive adenocarcinomas more frequently demonstrated tubuloglandular histology (100% vs. 25%, P=0.032) and were more frequently associated with precursor lesions exhibiting serrated morphology (66% vs. 6%, P=0.034). IDH1 mutations were also identified in the precursor dysplastic lesions associated with IDH1-positive adenocarcinomas. In conclusion, we demonstrate that IDH1 mutations are occasionally identified in inflammatory bowel disease-associated intestinal adenocarcinoma but not in intestinal adenocarcinoma not associated with inflammatory bowel disease. In addition, IDH1-mutated intestinal adenocarcinoma is associated with a characteristic low-grade tubuloglandular histology and often harbors concurrent KRAS mutations. Identification of patients with IDH1-mutated intestinal adenocarcinoma may become clinically important as new therapies emerge that target tumors that harbor IDH mutations.

BRAF-mutated microsatellite stable colorectal carcinoma: an aggressive adenocarcinoma with reduced CDX2 and increased cytokeratin 7 immunohistochemical expression

Reduced CDX2 and cytokeratin 20 (CK20) expression in colorectal carcinoma with BRAF mutation and high-level microsatellite instability (MSI-H) has been well documented. The immunophenotype of BRAF-mutated microsatellite stable (MSS) colorectal carcinoma has not been reported. We analyzed 205 colorectal carcinomas including 28 BRAF-mutated MSS, 53 BRAF-mutated MSI-H, and 124 BRAF wild-type MSS tumors for CDX2, cytokeratin 7 (CK7), and CK20 immunohistochemical expression. CDX2 was scored semiquantitatively for both staining intensity and percent of tumor cells staining and a modified CDX2 H-score was calculated. Patients with BRAF-mutated MSS colorectal carcinomas were more frequently stage IV at presentation compared to patients with BRAF-mutated MSI-H colorectal carcinomas and BRAF wild-type MSS colorectal carcinomas (32% versus 8% versus 15%, P < .001). BRAF-mutated MSS colorectal carcinoma displayed reduced CDX2 expression compared to BRAF wild-type MSS colorectal carcinoma (75% versus 94%; mean CDX2 H-score 98 versus 150, P < .001). CK7 expression was more often identified in BRAF-mutated MSS colorectal carcinoma compared to both BRAF-mutated MSI-H colorectal carcinoma and BRAF wild-type MSS colorectal carcinoma (39% versus 6% versus 6%, P = .0001). BRAF-mutated MSI-H colorectal carcinomas were less often CK20 positive compared to BRAF-mutated MSS and BRAF wild-type MSS tumors (70% versus 93% versus 90%, P = 0.001). In summary, BRAF-mutated MSS colorectal carcinoma often displays reduced CDX2 and increased CK7 expression. Knowledge of this altered immunophenotype is important as patients with BRAF-mutated MSS colorectal carcinoma often present with metastatic disease and the altered tumor immunophenotype may lead to the erroneous assumption that origin from the colon/rectum is unlikely.

Clinicopathologic features of synchronous colorectal carcinoma: A distinct subset arising from multiple sessile serrated adenomas and associated with high levels of microsatellite instability and favorable prognosis

Analysis of synchronous colorectal carcinomas can provide a unique model to examine the underlying molecular alterations in colorectal carcinoma, as synchronous tumors arise in a background of common genetic and environmental factors. We analyzed the clinicopathologic and molecular features of synchronous colorectal carcinomas compared with solitary carcinomas to correlate the histologic findings with molecular alterations and to identify the prognostic significance, if any, of synchronous colorectal carcinoma. Of the 4760 primary colorectal carcinomas resected for the years 2002 to 2012 at our institution, 58 patients (1.2%) harbored 2 invasive primary adenocarcinomas and comprise the synchronous colorectal carcinoma study group. A control group of consecutively resected solitary colorectal carcinomas from 109 patients was also analyzed. Compared with solitary colorectal carcinomas, synchronous colorectal carcinomas more frequently were identified in older patients (median age 70 vs. 60 y; P=0.001), involved the right colon (42/58, 72% vs. 47/109, 43%; P=0.0003), were more often microsatellite instability-high (MSI-H) (21/58, 36% vs. 13/109, 12%; P=0.0005), and were more frequently associated with precursor sessile serrated adenomas (SSAs) (13/58, 22% vs. 2/109, 2%; P=0.0001). A statistically significant difference in overall survival was identified between patients with synchronous and solitary colorectal carcinomas (5 y overall survival 92% vs. 56%, P=0.02). A unique subgroup of 13 synchronous colorectal carcinomas demonstrated tumors arising from SSAs (SSA-associated). All SSA-associated synchronous colorectal carcinomas were seen in patients above 65 years of age, and 12/13 (92%) occurred in women. Most patients (12/13, 92%) with SSA-associated synchronous colorectal carcinomas demonstrated involvement of the right colon, and tumors were frequently stage I or II (9/13, 69%) and low grade (11/13, 85%). In 12/13 (92%) SSA-associated synchronous colorectal carcinomas, both tumors exhibited loss of MLH1 and PMS2 immunohistochemical expression with concurrent BRAF V600E mutation. Nine of 13 (69%) patients with SSA-associated colorectal carcinoma harbored additional SSAs. Three of 13 (15%) patients with SSA-associated synchronous colorectal carcinoma met the World Health Organization criteria for serrated polyposis. Notably, no patient with SSA-associated synchronous colorectal carcinoma developed disease recurrence or died of disease at last follow-up. In conclusion, synchronous colorectal carcinomas are enriched with MSI-H tumors, particularly those arising from SSAs, which contributes to the overall improved survival for patients with synchronous tumors compared with patients with solitary tumors. We demonstrate that SSA-associated synchronous colorectal carcinomas have a striking predilection for elderly women, are associated with a favorable prognosis, and are MSI-H and BRAF V600E positive.

Clinicopathological features of nonsmall cell lung carcinomas with BRAF mutations

BACKGROUND

Recently, driver tyrosine kinase gene mutations have been detected in malignant tumors, including lung tumors. Notwithstanding their attractiveness as targets for molecular therapy, limited information is available regarding BRAF-mutated lung carcinomas.

MATERIALS AND METHODS

BRAF mutation status was determined in 2001 surgically resected nonsmall-cell lung cancer (NSCLC) cases using high-resolution melting analysis (HRMA) followed by Sanger sequencing and/or deep sequencing using next generation sequencer.

RESULTS

BRAF mutations were detected in 26 (1.3%) of 2001 NSCLC cases (25 adenocarcinomas and 1 squamous cell carcinoma). In the 26 cases, 13 mutation genotypes were identified, including V600E (8 of 26; 30.8%), G469A (6 of 26; 23.1%), K601E (4 of 26; 15.4%), and other residual mutations (1 of 26; 0.04%). Of the 13 genotypes, 4 genotypes (G464E, G596R, A598T, and G606R) had not been previously reported in lung cancer. The overall survival rate was not significantly different between patients with wild-type BRAF and those with V600E or non-V600E BRAF mutations (P = 0.49 and P = 0.15, respectively). Histomorphological analysis revealed that focal clear cell changes were present in 75% of V600E-mutated tumors. All V600E BRAF-mutated tumors were negative for other driver gene alterations including epidermal growth factor receptor (EGFR) and KRAS mutations and the anaplastic lymphoma kinase gene translocation, whereas five tumors with non-V600E BRAF mutations (four G469A and one G464E/G466R) showed concomitant EGFR mutations.

CONCLUSION

The frequency of BRAF mutations in lung cancer was low in an Asian cohort. Furthermore, BRAF mutation status lacked prognostic significance in this patient population.

The role of molecular analyses in the diagnosis and treatment of non-small-cell lung carcinomas

Non-small-cell lung cancer (NSCLC) subtyping has recently been a key factor in determining patient management with novel drugs. In addition, the identification of distinct oncogenic driver mutations frequently associated with NSCLC histotype and coupled to the clinical responses to targeted therapies have revolutionized the impact of histologic type and molecular biomarkers in lung cancer. Several molecular alterations involving different genes (EGFR, KRAS, ALK, BRAF, and HER2) seem to have a remarkable predilection for adenocarcinoma and specific inhibitors of EGFR and ALK are now available for patients with adenocarcinoma harboring the relevant gene alterations. The efficacy of histology-based and molecular-targeted therapies had a deep impact in (1) re-defining classification of lung cancer (particularly adenocarcinomas) and (2) routine clinical practice of pathologists involved in optimization of handling of tissue samples in order to guarantee NSCLC subtyping with the help of immunohistochemistry and adequately preserve tumor cells for molecular analysis. In agreement with the modern multidisciplinary approach to lung cancer, we reviewed here the diagnostic and predictive value of molecular biomarkers according to the clinical, pathologic, and molecular biologist viewpoints.

Immunohistochemical detection of BRAF V600E mutant protein using the VE1 antibody in colorectal carcinoma is highly concordant with molecular testing but requires rigorous antibody optimization

The BRAF V600E mutation occurs in 15% of colorectal carcinomas (CRCs) and has important genetic, prognostic, and therapeutic implications. A monoclonal antibody (VE1) targeting the BRAF V600E mutant protein has become available with variable efficacy in literature reports. We investigated the utility of the VE1 antibody in detecting BRAF V600E mutant protein in two cohorts: (1) a retrospectively accrued series of 103 resected CRCs with (N = 57) and without (N = 46) known BRAF V600E mutation status by PCR and (2) a prospective series of 25 CRCs requiring BRAF analysis during routine screening for Lynch syndrome. All 74 cases with positive BRAF V600E mutation demonstrated cytoplasmic positivity with the VE1 antibody with most tumors (70/74, 95%) demonstrating moderate to strong staining. Of the 54 BRAF V600E-negative cases, 51/54 CRCs (94%) were negative with the VE1 antibody while 3 CRCs (6%) demonstrated weak cytoplasmic staining. The sensitivity and specificity of VE1 was 100% and 94%, respectively. Ten BRAF V600E-mutated CRCs had adjacent precursor lesions including 7 sessile serrated adenomas associated with CRCs with high-level microsatellite instability (MSI-H). All 10 precursor adenomas were positive for VE1 staining with the 7 sessile serrated adenomas maintaining preserved MLH1 expression. Our results indicate that VE1 immunohistochemistry is a useful surrogate for the detection of the BRAF V600E mutation in CRC, although weak staining must be evaluated by BRAF PCR analysis to exclude a false positive result. In addition, the BRAF V600E mutation appears to be an early event before the divergent development into MSS and MSI-H pathways.

Rare mutations in non-small-cell lung cancer

In the last decade, new insights in molecular biology have changed the therapeutic landscape of non-small-cell lung cancer. Since 2004, when activating mutations of the EGFR were firstly identified, several genetic aberrations have been discovered, mainly in adenocarcinoma. EGFR mutations are a relatively frequent event in non-small-cell lung cancer, generally consisting of exon 19 deletion or exon 21 substitution. In adenocarcinoma, additional rare mutations are detectable in the EGFR gene, as well as in other genes, including ALK, ROS1, RET, HER2 and BRAF. Recent studies in squamous cell carcinoma identified TP53 as the most frequent mutation, followed by additional more rare mutations, including PI3KCA, PTEN, DDR2 and FGFR. The aim of the present review is to analyze the potential prognostic and predictive role of rare mutations.

Comparison of EGFR signaling pathway somatic DNA mutations derived from peripheral blood and corresponding tumor tissue of patients with advanced non-small-cell lung cancer using liquidchip technology

Somatic DNA mutations affecting the epidermal growth factor receptor (EGFR) signaling pathway are known to predict responsiveness to EGFR-tyrosine kinase inhibitor drugs in patients with advanced non-small-cell lung cancers. We evaluated a sensitive liquidchip platform for detecting EGFR, KRAS (alias Ki-ras), proto-oncogene B-Raf, and phosphatidylinositol 3-kinase CA mutations in plasma samples, which were highly correlated with matched tumor tissues from 86 patients with advanced non-small-cell lung cancers. Either EGFR exon 19 or 21 mutations were detected in 36 patients: 23 of whom had identical mutations in both their blood and tissue samples; whereas mutations in the remaining 13 were found only in their tumor samples. These EGFR mutations occurred at a significantly higher frequency in females, never-smokers, and in patients with adenocarcinomas (P ≤ 0.001). The EGFR exon 20 T790M mutation was detected in only one of the paired samples [100% (95% CI, 96% to 100%) agreement]. For KRAS, proto-oncogene B-Raf, and phosphatidylinositol 3-kinase CA mutations, the overall agreements were 97% (95% CI, 90% to 99%), 98% (95% CI, 92% to 99%), and 97% (95% CI, 90% to 99%), respectively, and these were not associated with age, sex, smoking history, or histopathologic type. In conclusion, mutations detected in plasma correlated strongly with mutation profiles in each respective tumor sample, suggesting that this liquidchip platform may offer a rapid and noninvasive method for predicting tumor responsiveness to EGFR-tyrosine kinase inhibitor drugs in patients with advanced non-small-cell lung cancers.

Pulmonary Langerhans cell histiocytosis: profiling of multifocal tumors using next-generation sequencing identifies concordant occurrence of BRAF V600E mutations

BACKGROUND

Pulmonary Langerhans cell histiocytosis is a localized proliferation of Langerhans cells in the lung that presents without systemic manifestations as bilateral nodular lung disease in adult cigarette smokers. The molecular basis for this proliferation is unknown.

METHODS

Twenty-two concurrent nodules in five patients were microdissected from formalin-fixed paraffin-embedded tissue and analyzed by next-generation sequencing for mutations in 46 cancer genes with the Ion AmpliSeq Cancer Panel on an Ion PGM (Personal Genome Machine) Sequencer (Life Technologies Corporation). Mutation confirmation was performed by conventional Sanger sequencing or by sensitive coamplification at lower denaturation polymerase chain reaction/fluorescence melting curve analysis.

RESULTS

Small amounts of DNA (10 ng) isolated from nodules were sufficient for successful interrogation of 740 mutational hot spots in 46 cancer genes by the Ion PGM Sequencer, with an average depth of coverage of 2,783 reads per hot spot and with uniformity of coverage of 92%. BRAF V600E mutation was detected in all concurrent nodules studied in two of the five patients, whereas in three of the five patients, no oncogene mutations were found.

CONCLUSIONS

Pulmonary Langerhans cell histiocytosis appears to be a clonal proliferation that may or may not have BRAF V600E mutations. For those with BRAF V600E mutations, new targeted therapies, such as vemurafenib, may be used in progressive cases.

Lung adenocarcinoma in the era of targeted therapies: histological classification, sample prioritization, and predictive biomarkers

The arrival of targeted therapies has presented both a conceptual and a practical challenge in the treatment of patients with advanced non-small cell lung carcinomas (NSCLCs). The relationship of these treatments with specific histologies and predictive biomarkers has made the handling of biopsies the key factor for success. In this study, we highlight the balance between precise histological diagnosis and the practice of conducting multiple predictive assays simultaneously. This can only be achieved where there is a commitment to multidisciplinary working by the tumor board to ensure that a sensible protocol is applied. This proposal for prioritizing samples includes both recent technological advances and the some of the latest discoveries in the molecular classification of NSCLCs.

Lung cancer in never-smokers. Does smoking history matter in the era of molecular diagnostics and targeted therapy?

Lung cancer in never-smokers was recognised as a distinct clinical entity around the mid-2000s because these patients tended to be Asian women and diagnosed at a younger age with a preponderance of adenocarcinoma and better survival outcome despite a more advanced stage of presentation. It was soon discovered that lung cancer in never-smokers had a higher prevalence of activating EGFR mutations and we tend to classify lung cancer by smoking status for screening purpose. With the discoveries of many actionable driver mutations such as activating EGFR mutations and ALK rearrangement in adenocarcinoma of the lung we have switched to classifying non-small cell lung cancer into different individual molecular subgroups based on the presence of a dominant driver mutation. Although many actionable driver mutations are found in never-smokers with adenocarcinoma, this review will summarise that a substantial proportion of patients with these actionable driver mutations had a previous smoking history. Alternatively among the driver mutations that are associated with smoking history, a fair amount of these patients were never-smokers. Thus smoking status should not be used as a screen strategy for identifying driver mutations in clinical practice. Finally smoking history may have predictive and/or prognostic significance within individual molecular subgroups and identifying the difference according to smoking history may help optimise future targeted therapy.

Diagnosis of lung adenocarcinoma in resected specimens: implications of the 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification

A new lung adenocarcinoma classification has been published by the International Association for the Study of Lung Cancer, the American Thoracic Society, and the European Respiratory Society. This new classification is needed to provide uniform terminology and diagnostic criteria, most especially for bronchioloalveolar carcinoma. It was developed by an international core panel of experts representing all 3 societies with oncologists/pulmonologists, pathologists, radiologists, molecular biologists, and thoracic surgeons.This summary focuses on the aspects of this classification that address resection specimens. The terms bronchioloalveolar carcinoma and mixed subtype adenocarcinoma are no longer used. For resection specimens, new concepts are introduced, such as adenocarcinoma in situ and minimally invasive adenocarcinoma for small solitary adenocarcinomas with either pure lepidic growth (adenocarcinoma in situ) and predominant lepidic growth with invasion of 5 mm or less (minimally invasive adenocarcinoma), to define the condition of patients who will have 100% or near 100% disease-specific survival, respectively, if they undergo complete lesion resection. Adenocarcinoma in situ and minimally invasive adenocarcinoma are usually nonmucinous, but rarely may be mucinous. Invasive adenocarcinomas are now classified by predominant pattern after using comprehensive histologic subtyping with lepidic (formerly most mixed subtype tumors with nonmucinous bronchioloalveolar carcinoma), acinar, papillary, and solid patterns; micropapillary is added as a new histologic subtype. Variants include invasive mucinous adenocarcinoma (formerly mucinous bronchioloalveolar carcinoma), colloid, fetal, and enteric adenocarcinoma.It is possible that this classification may impact the next revision of the TNM staging classification, with adjustment of the size T factor according to only the invasive component pathologically in adenocarcinomas with lepidic areas.

Targeted agents in non-small cell lung cancer therapy: What is there on the horizon?

Lung cancer is a heterogeneous group of diseases. There has been much research in lung cancer over the past decade which has advanced our ability to treat these patients with a more personalized approach. The scope of this paper is to review the literature and give a broad understanding of the current molecular targets for which we currently have therapies as well as other targets for which we may soon have therapies. Additionally, we will cover some of the issues of resistance with these targeted therapies. The molecular targets we intend to discuss are epidermal growth factor receptor (EGFR), Vascular endothelial growth factor (VEGF), anaplastic large-cell lymphoma kinase (ALK), KRAS, C-MET/RON, PIK3CA. ROS-1, RET Fibroblast growth factor receptor (FGFR). Ephrins and their receptors, BRAF, and immunotherapies/vaccines. This manuscript only summarizes the work which has been done to date and in no way is meant to be comprehensive.