KRAS mutation-driven angiopoietin 2 bestows anti-VEGF resistance in epithelial carcinomas.

Defining reliable surrogate markers and overcoming drug resistance are the most challenging issues for improving therapeutic outcomes of antiangiogenic drugs (AADs) in cancer patients. At the time of this writing, no biomarkers are clinically available to predict AAD therapeutic benefits and drug resistance. Here, we uncovered a unique mechanism of AAD resistance in epithelial carcinomas with KRAS mutations that targeted angiopoietin 2 (ANG2) to circumvent antivascular endothelial growth factor (anti-VEGF) responses. Mechanistically, KRAS mutations up-regulated the FOXC2 transcription factor that directly elevated ANG2 expression at the transcriptional level. ANG2 bestowed anti-VEGF resistance as an alternative pathway to augment VEGF-independent tumor angiogenesis. Most colorectal and pancreatic cancers with KRAS mutations were intrinsically resistant to monotherapies of anti-VEGF or anti-ANG2 drugs. However, combination therapy with anti-VEGF and anti-ANG2 drugs produced synergistic and potent anticancer effects in KRAS-mutated cancers. Together, these data demonstrate that KRAS mutations in tumors serve as a predictive marker for anti-VEGF resistance and are susceptible to combination therapy with anti-VEGF and anti-ANG2 drugs.

Is Precision Surgery Applicable to Colorectal Liver Metastases? A Systematic Review and Meta-analysis of Studies that Investigate the Association of Surgical Technique with Outcomes in the Context of Distinct Tumor Biology.

BACKGROUND: Although some data suggest that patients with mutRAS colorectal liver metastases (CRLM) may benefit from anatomic hepatectomy, this topic remains controversial. We performed a systematic review and meta-analysis to determine whether RAS mutation status was associated with prognosis relative to surgical technique [anatomic resection (AR) vs. nonanatomic resection (NAR)] among patients with CRLM. PATIENTS AND METHODS: A systematic review and meta-analysis of studies were performed to investigate the association of AR versus NAR with overall and liver-specific disease-free survival (DFS and liver-specific DFS, respectively) in the context of RAS mutation status. RESULTS: Overall, 2018 patients (831 mutRAS vs. 1187 wtRAS) were included from five eligible studies. AR was associated with a 40% improvement in liver-specific DFS [hazard ratio (HR) = 0.6, 95% confidence interval (CI) 0.44-0.81, p = 0.01] and a 28% improvement in overall DFS (HR = 0.72, 95% CI 0.54-0.95, p = 0.02) among patients with mutRAS tumors; in contrast, AR was not associated with any improvement in liver-specific DFS or overall DFS among wtRAS patients. These differences may have been mediated by the 40% decreased incidence in R1 resection among patients with mutRAS tumors who underwent AR versus NAR [relative risk (RR): 0.6, 95% CI 0.40-0.91, p = 0.02]. In contrast, the probability of an R1 resection was not decreased among wtRAS patients who underwent AR versus NAR (RR: 0.93, 95% CI 0.69-1.25, p = 0.62). CONCLUSIONS: The data suggest that precision surgery may be relevant to CRLM. Specifically, rather than a parenchymal sparing dogma for all patients, AR may have a role in individuals with mutRAS tumors.

Development and external validation of MRI-based RAS mutation status prediction model for liver metastases of colorectal cancer.

BACKGROUND: The mutation status of rat sarcoma viral oncogene homolog (RAS) has prognostic significance and serves as a key predictive biomarker for the effectiveness of antiepidermal growth factor receptor (EGFR) therapy. However, there remains a lack of effective models for predicting RAS mutation status in colorectal liver metastases (CRLMs). This study aimed to construct and validate a diagnostic model for predicting RAS mutation status among patients undergoing hepatic resection for CRLMs. METHODS: A diagnostic multivariate prediction model was developed and validated in patients with CRLMs who had undergone hepatectomy between 2014 and 2020. Patients from Institution A were assigned to the model development group (i.e., Development Cohort), while patients from Institutions B and C were assigned to the external validation groups (i.e., Validation Cohort_1 and Validation Cohort_2). The presence of CRLMs was determined by examination of surgical specimens. RAS mutation status was determined by genetic testing. The final predictors, identified by a group of oncologists and radiologists, included several key clinical, demographic, and radiographic characteristics derived from magnetic resonance images. Multiple imputation was performed to estimate the values of missing non-outcome data. A penalized logistic regression model using the adaptive least absolute shrinkage and selection operator penalty was implemented to select appropriate variables for the development of the model. A single nomogram was constructed from the model. The performance of the prediction model, discrimination, and calibration were estimated and reported by the area under the receiver operating characteristic curve (AUC) and calibration plots. Internal validation with a bootstrapping procedure and external validation of the nomogram were assessed. Finally, decision curve analyses were used to characterize the clinical outcomes of the Development and Validation Cohorts. RESULTS: A total of 173 patients were enrolled in this study between January 2014 and May 2020. Of the 173 patients, 117 patients from Institution A were assigned to the Model Development group, while 56 patients (33 from Institution B and 23 from Institution C) were assigned to the Model Validation groups. Forty-six (39.3%) patients harbored RAS mutations in the Development Cohort compared to 14 (42.4%) in Validation Cohort_1 and 8 (34.8%) in Validation Cohort_2. The final model contained the following predictor variables: time of occurrence of CRLMs, location of primary lesion, type of intratumoral necrosis, and early enhancement of liver parenchyma. The diagnostic model based on clinical and MRI data demonstrated satisfactory predictive performance in distinguishing between mutated and wild-type RAS, with AUCs of 0.742 (95% confidence interval [CI]: 0.651─0.834), 0.741 (95% CI: 0.649─0.836), 0.703 (95% CI: 0.514─0.892), and 0.708 (95% CI: 0.452─0.964) in the Development Cohort, bootstrapping internal validation, external Validation Cohort_1 and Validation Cohort_2, respectively. The Hosmer-Lemeshow goodness-of-fit values for the Development Cohort, Validation Cohort_1 and Validation Cohort_2 were 2.868 (p = 0.942), 4.616 (p = 0.465), and 6.297 (p = 0.391), respectively. CONCLUSIONS: Integrating clinical, demographic, and radiographic modalities with a magnetic resonance imaging-based approach may accurately predict the RAS mutation status of CRLMs, thereby aiding in triage and possibly reducing the time taken to perform diagnostic and life-saving procedures. Our diagnostic multivariate prediction model may serve as a foundation for prognostic stratification and therapeutic decision-making.

Predictive nomograms of repeat intrahepatic recurrence and overall survival after radiofrequency ablation of recurrent colorectal liver metastases.

OBJECTIVES: This study was conducted to develop nomograms for predicting repeat intrahepatic recurrence (rIHR) and overall survival (OS), after radiofrequency ablation (RFA), treatment in patients with recurrent colorectal liver metastases (CLMs) after hepatectomy based on clinicopathologic features. METHODS: A total of 160 consecutive patients with recurrent CLMs after hepatectomy who were treated with ultrasound-guided percutaneous RFA from 2012 to 2022 were retrospectively included. Patients were randomly divided into a training cohort and a validation cohort, with a ratio of 8:2. Potential prognostic factors associated with rIHR and OS, after RFA, were identified by using the competing-risks and Cox proportional hazard models, respectively, and were used to construct the nomogram. The nomogram was evaluated by Harrell's C-index and a calibration curve. RESULTS: The 1-, 2-, and 3-year rIHR rates after RFA were 58.8%, 70.2%, and 74.2%, respectively. The 1-, 3- and 5-year OS rates were 96.3%, 60.4%, and 38.5%, respectively. In the multivariate analysis, mutant RAS, interval from hepatectomy to intrahepatic recurrence ≤ 12 months, CEA level >5 ng/ml, and ablation margin <5 mm were the independent predictive factors for rIHR. Mutant RAS, largest CLM at hepatectomy >3 cm, CEA level >5 ng/ml, and extrahepatic disease were independent predictors of poor OS. Two nomograms for rIHR and OS were constructed using the respective significant variables. In both cohorts, the nomogram demonstrated good discrimination and calibration. CONCLUSIONS: The established nomograms can predict individual risk of rIHR and OS after RFA for recurrent CLMs and contribute to improving individualized management.

Dual targeted therapy with pyrotinib and trastuzumab for HER2-positive advanced colorectal cancer: A phase 2 trial.

This trial was initiated to evaluate the efficacy and safety of pyrotinib in combination with trastuzumab in patients with human epidermal growth factor receptor 2 (HER2)-positive recurrent/metastatic colorectal cancer (CRC). In this single-arm, open-label, multicenter, phase 2 trial patients with HER2-positive recurrent/metastatic CRC were enrolled and received oral pyrotinib 400 mg once a day plus intravenous trastuzumab 8 mg/kg loading dose followed by 6 mg/kg once every 3 weeks. The primary endpoint was the objective response rate (ORR). Disease control rate (DCR), progression-free survival (PFS), duration of response, and safety were assessed as secondary endpoints. From December 2019 to October 2021, a total of 20 patients were enrolled and 18 of them were evaluable for response. All patients were B-rapidly accelerated fibrosarcoma (BRAF) wild type. Four patients achieved partial response, with an ORR of 22.2% (4/18, 95% confidence interval [CI] 6.4-47.6) and DCR of 61.1% (11/18, 95% CI 35.8-82.7), while the ORR and DCR were 33.3% (4/12, 95% CI 13.8-60.9) and 83.3% (10/12, 95% CI 51.6-97.9), respectively, in RAS wild-type patients. At the time of cut-off day, median follow-up was 10.7 months (range 3.8-13.8). The median PFS was 3.4 months (95% CI 1.8-4.3) in the overall population and 4.3 months (95% CI 3.2-8.5) in the RAS wild-type group. The most common adverse event of grade ≥3 was diarrhea (13/20, 65.0%). Pyrotinib combined with trastuzumab showed promising antitumor activity and a manageable safety profile in patients with RAS/BRAF wild-type HER2-positive advanced CRC.

Phase Ib/II Study of the Efficacy and Safety of Binimetinib (MEK162) Plus Panitumumab for Mutant or Wild-Type RAS Metastatic Colorectal Cancer.

INTRODUCTION: Activating RAS gene mutations occur in approximately 55% of patients with metastatic colorectal cancer (mCRC) and are associated with poorer clinical outcomes due to epidermal growth factor receptor (EGFR) blockade resistance. Combined EGFR and mitogen-activated protein kinase (MEK) inhibition may extend response to EGFR inhibition and overcome acquired resistance. This phase Ib/II dose escalation trial evaluated the safety and activity of dual inhibition with binimetinib (MEK1/2 inhibitor) and panitumumab (EGFR inhibitor [EGFRi]) in patients with RAS mutant or BRAF wild type (WT)/RAS WT mCRC. METHODS: Phase Ib dose escalation started with binimetinib 45 mg twice daily plus panitumumab 6 mg/kg administered every 2 weeks. In the phase II study, patients with measurable mCRC were enrolled into 4 groups based on previous anti-EGFR monoclonal antibody therapy and RAS mutational status. RESULTS: No patients in the phase Ib portion (n = 10) had a response; 70% of patients had stable disease. In the phase II portion (n = 43), overall response rate (ORR, confirmed) was 2.3% with one partial response in the RAS WT group, DCR was 30.2%, and median progression-free survival was 1.8 months (95%CI, 1.6-3.3). All patients experienced ≥1 adverse event, with the most common being diarrhea (71.7%), vomiting (52.8%), nausea (50.9%), fatigue (49.1%), dermatitis acneiform (43.4%), and rash (41.5%). Most patients required treatment interruption or dose reduction due to difficulties tolerating treatment. CONCLUSIONS: The combination of binimetinib and panitumumab had substantial toxicity and limited clinical activity for patients with mutant or WT RAS mCRC, independent of EGFRi treatment history (Trial registration: NCT01927341).

BRAF V600E/RAS Mutations and Lynch Syndrome in Patients With MSI-H/dMMR Metastatic Colorectal Cancer Treated With Immune Checkpoint Inhibitors.

BACKGROUND: We pooled data from 2 cohorts of immune checkpoint inhibitors-treated microsatellite instability-high/mismatch repair-deficient (MSI/dMMR) metastatic colorectal cancer patients to evaluate the prognostic value of RAS/BRAFV600E mutations and Lynch syndrome (LS). PATIENTS AND METHODS: Patients were defined as LS-linked if germline mutation was detected and as sporadic if loss of MLH1/PMS2 expression with BRAFV600E mutation and/or MLH1 promoter hypermethylation, or biallelic somatic MMR genes mutations were found. Progression-free survival (PFS) and overall survival (OS) were adjusted on prognostic modifiers selected on unadjusted analysis (P < .2) if limited number of events. RESULTS: Of 466 included patients, 305 (65.4%) and 161 (34.5%) received, respectively, anti-PD1 alone and anti-PD1+anti-CTLA4 in the total population, 111 (24.0%) were treated in first-line; 129 (28.8%) were BRAFV600E-mutated and 153 (32.8%) RAS-mutated. Median follow-up was 20.9 months. In adjusted analysis of the whole population (PFS/OS events = 186/133), no associations with PFS and OS were observed for BRAFV600E-mutated (PFS HR= 1.20, P = .372; OS HR = 1.06, P = .811) and RAS-mutated patients (PFS HR = 0.93, P = .712, OS HR = 0.75, P = .202). In adjusted analysis in the Lynch/sporadic status-assigned population (n = 242; PFS/OS events = 80/54), LS-liked patients had an improved PFS compared to sporadic cases (HR = 0.49, P = .036). The adjusted HR for OS was 0.56 with no significance (P = .143). No adjustment on BRAFV600E mutation was done due to collinearity. CONCLUSION: In this cohort, RAS/BRAFV600E mutations were not associated with survival while LS conferred an improved PFS.

Different prognostic values of KRAS exon 2 submutations and BRAF V600E mutation in microsatellite stable (MSS) and unstable (MSI) stage III colon cancer: an ACCENT/IDEA pooled analysis of seven trials.

BACKGROUND: The prognostic value of KRAS and BRAFV600E mutations in stage III colon cancer (CC) remains controversial and has never been clearly analyzed in patients with microsatellite instability-high (MSI-H) tumors due to sample size limitations. Data are also lacking for KRAS submutations and prognosis. PATIENTS AND METHODS: We examined clinicopathological variables and prognosis in patients with surgically resected stage III CC who participated in seven clinical trials from the ACCENT/IDEA databases. Associations between KRAS exon 2 and BRAFV600E mutations and time to recurrence (TTR), overall survival (OS), and survival after recurrence (SAR) were assessed using a Cox model. We also analyzed the prognostic value of KRAS exon 2 submutations. RESULTS: Among 8460 patients, 11.4% had MSI-H status. In the MSI-H group, BRAFV600E, KRAS exon 2 mutants, and double-wild-type statuses were detected in 40.6%, 18.1%, and 41.3%, respectively, whereas and in the microsatellite stable (MSS) group, these were detected in 7.7%, 38.6%, and 53.8%, respectively. In the MSS group, 5-year TTR rates of 61.8%, 66.3%, and 72.9% were observed among patients with BRAFV600E, KRAS exon 2 mutants, and those who were DWT, respectively [adjusted hazard ratio (HR) = 1.58 and 1.31, both P < 0.001]. In the MSI-H group, 5-year TTR rates did not differ significantly among the mutated subgroups. Similar results were found for OS. However, survival after relapse was significantly shorter in the KRAS exon 2- and BRAFV600E-mutated patients in both MSS (adjusted HR = 2.06 and 1.15; both P < 0.05) and MSI-H (adjusted HR = 1.99 and 1.81; both P < 0.05) groups. In the MSS group, KRAS exon 2 mutations were associated with TTR, but only p.G12C, p.G12D, and p.G13D were associated with poor outcomes after disease recurrence. CONCLUSIONS: Testing for both KRAS and BRAFV600E mutations in stage III patients should be considered as they can better define individual patient prognosis, and may also enable patient selection for (neo)adjuvant trials dedicated to specific molecular subtypes with poor prognosis.

RAS signaling and immune cells: a sinister crosstalk in the tumor microenvironment.

The rat sarcoma virus (RAS) gene is the most commonly mutated oncogene in cancer, with about 19% of cancer patients carrying RAS mutations. Studies on the interaction between RAS mutation and tumor immune microenvironment (TIM) have been flourishing in recent years. More and more evidence has proved that RAS signals regulate immune cells' recruitment, activation, and differentiation while assisting tumor cells to evade immune surveillance. This review concluded the direct and indirect treatment strategies for RAS mutations. In addition, we updated the underlying mechanisms by which RAS signaling modulated immune infiltration and immune escape. Finally, we discussed advances in RAS-targeted immunotherapies, including cancer vaccines and adoptive cell therapies, with a particular focus on combination strategies with personalized therapy and great potential to achieve lasting clinical benefits.

New Developments in Treating RAS-Mutated Metastatic Colorectal Cancer.

OPINION STATEMENT: One of the great challenges in digestive oncology is choosing the optimal therapy for RAS-mutated metastatic colorectal cancer (mCRC). Even though the RAS genes and accompanying pathway were identified decades ago and extensive knowledge exists on their role in carcinogenesis, it has proven challenging to translate these insights into new therapies and clinical benefit for patients. However, recently, new drugs targeting this pathway (for example, KRASG12C inhibitors) have shown promising results in clinical trials, as monotherapy or in combination regimens. Although resistance remains an important issue, more knowledge on adaptive resistance and feedback loops in the RAS-pathway has led to strategical combination regimens to overcome this problem. In the past year, many encouraging results have been published or presented at conferences. Even though some of the data is still preliminary, these studies may bring practice-changing results and can lead to a clinical benefit for patients over the coming years. Because of these recent developments, the treatment of RAS-mutated mCRC has become a topic of great interest. Therefore, in this review, we will summarize the standard of care and discuss the most important emerging therapies for this patient population.

Morphological, immunohistochemical, and genetic analyses of epithelioid gastrointestinal stromal tumors.

Epithelioid gastrointestinal stromal tumors (GISTs) are rare and may be confused with other tumors with epithelioid morphology. Therefore, herein, we collected 12 epithelioid GIST samples and summarized their morphological and immunohistochemical characteristics. Through genetic testing, we explored the correlation between morphology and gene mutations. The results showed that eight tumors showed focal or diffuse myxoid stromal changes with less cohesively arranged rhabdoid tumor cells; among these, five showed platelet-derived growth factor receptor alpha gene (PDGFRA) mutations. Signet ring cells with sclerosing stroma and receptor tyrosine kinase type III gene (KIT) mutations were present in two cases, which might be a KIT mutation-associated growth pattern in epithelioid GISTs. Succinate dehydrogenase gene (SDH) mutations were detected in three cases. Simultaneously, PDGFRA mutations were detected in two cases, and the Kirsten rat sarcoma viral oncogene homolog gene (KRAS) mutation was detected in another case. SDH-subunit B (SDHB) expression was partially weak and strongly diffuse in two cases with concurrent PDGFRA and SDHD mutations, respectively. The coexistence of PDGFRA and SDHD mutations may have affected SDHB expression. Altogether, we concluded that PDGFRA mutations may play an important role in co-mutant GIST pathogenesis.

KRAS and NRAS mutational analysis in plasma ctDNA from patients with metastatic colorectal cancer by real-time PCR and digital PCR.

PURPOSE: Mutations in the KRAS and NRAS (RAS) genes are negative predictors of response to anti-EGFR therapy in metastatic colorectal cancer (mCRC). The detection of mutations in circulating tumor DNA (ctDNA) has emerged as a less invasive strategy to assess the molecular profile of mCRC patients. We aimed to perform RAS mutational analysis in ctDNA from mCRC patients using BEAMing Digital PCR (OncoBEAM) and Idylla ctDNA qPCR and evaluate the concordance rate with RAS mutational status in tumor tissue and between these two methodologies with different limits of detection. METHODS: Blood samples were collected from 47 mCRC patients previously tested for RAS mutations in tumor tissue. DNA was extracted from plasma using the QIAamp Circulating Nucleic Acid Kit, and RAS mutation analysis was conducted using OncoBEAM RAS CRC and Idylla ctRAS assays. RESULTS: The overall agreement between tumor tissue and ctDNA analyses was 83% and 78.7% using the OncoBEAM and Idylla assays, respectively, with the concordance being 96.2% and 88.5% in naive treatment patients. The overall agreement between OncoBEAM and Idylla ctDNA analyses was 91.7%. CONCLUSIONS: Analysis of ctDNA is a viable strategy for clinical management of mCRC patients. Although the OncoBEAM assay sensitivity is somewhat higher, the fully automated Idylla platform also has good performance, while being cheaper and much less labor-intensive, for the detection of RAS mutations in plasma, either at diagnosis or after progression when considering anti-EGFR treatment rechallenge.

Association of Anti-EGFR Antibody and MEK Inhibitor in Gynecological Cancer Harboring RAS Mutation: A Case Series.

Low-grade serous carcinoma represents a minority of serous carcinoma. Although they have better prognosis than high-grade serous carcinoma, they respond poorly to chemotherapy. Thus, it appears necessary to find other treatments such as targeted therapies. Since RAS or RAF mutations occur frequently in low-grade serous carcinoma and lead to constitutively activated MAPK cascade, MEK inhibition should be effective in the treatment of low-grade serous carcinoma. So, we wanted to evaluate the clinical benefit of MEK inhibitors in the management of advanced-stage low-grade serous carcinoma harboring KRAS or NRAS mutation. We report a case series of three women with advanced-stage low-grade serous carcinoma harboring RAS mutation who had stabilization of their disease during several months under targeted therapy combining anti-EGFR antibody and MEK inhibitor. We performed in vitro experiments, confirming the effectiveness of MEK inhibitor on the KRAS-mutated OVCAR-5 cell line, and the constitutively activation of MAPK cascade in RAS-mutated carcinoma. However, it seems that the anti-EGFR antibody does not provide any additional benefit. After whole exome analysis is carried out on the patient with the shortest response, we observed the appearance of RB1 loss-of-function mutation that could be a mechanism of resistance to MEK inhibitors in RAS- of RAF-mutated cancers. The MEK inhibitor is effective in the advanced stages of low-grade serous carcinoma harboring RAS mutation with acceptable tolerance. RB1 loss could be a mechanism of resistance to MEK inhibitors in RAS-mutated low-grade serous carcinoma.

Cetuximab plus irinotecan administered biweekly with reduced infusion time to heavily pretreated patients with metastatic colorectal cancer and related RAS and BRAF mutation status.

Metastatic colorectal cancer (mCRC) is treated with cetuximab 250 mg/m2 administered weekly over 1 hour or biweekly (q2w) over 3.5 hours when combined with irinotecan. This prospective study investigated cetuximab 500 mg/m2 plus irinotecan 180 mg/m2 administered q2w over 1.5 hours independent of RAS or BRAF mutation status in mCRC patients in a third-line setting. The intention-to-treat population included 181 patients. No patients had complete response, 18% had partial responses (PR) and 48% stable disease (SD). For cetuximab, a relative dose intensity of ≥90% was reached in 78% and for irinotecan in 67% of the patients. Grade 3 to 4 toxicities were pain (17%), fatigue (9%), neutropenia (8%), diarrhea (8%), rash (8%), infection (7%) and hypersensitivity (3%). No deaths occurred. Next-generation sequencing in 96.7% of the patients revealed that 50.3% had RAS and BRAFV600E wild type (WT), with a mutation type (MT) in 45.1% of the RAS and 4.4% of the BRAFV600E genes. In patients with RAS-WT and RAS-MT tumors, a PR was obtained in 32% and 4% (P = .000003) and an SD in 43% and 53%, respectively, with a superior PFS (6.2 vs 3.7 months; hazard ratio [HR] 2.12, P = .00001) and OS (12.9 vs 8.8 months; HR 1.71, P = .0008). Treatment efficacy was poor in 7.4% of patients with an RAS mutation outside KRAS exon 2 and in 38% of patients with KRAS exon 2 mutations. Administration of cetuximab and irinotecan q2w, shortening treatment time from 3.5 to 1.5 hours, is recommended as standard therapy.

Infrequent RAS mutation is not associated with specific histological phenotype in gliomas.

BACKGROUND: Mutations in driver genes such as IDH and BRAF have been identified in gliomas. Meanwhile, dysregulations in the p53, RB1, and MAPK and/or PI3K pathways are involved in the molecular pathogenesis of glioblastoma. RAS family genes activate MAPK through activation of RAF and PI3K to promote cell proliferation. RAS mutations are a well-known driver of mutation in many types of cancers, but knowledge of their significance for glioma is insufficient. The purpose of this study was to reveal the frequency and the clinical phenotype of RAS mutant in gliomas. METHODS: This study analysed RAS mutations and their clinical significance in 242 gliomas that were stored as unfixed or cryopreserved specimens removed at Kyoto University and Osaka National Hospital between May 2006 and October 2017. The hot spots mutation of IDH1/2, H3F3A, HIST1H3B, and TERT promoter and exon 2 and exon 3 of KRAS, HRAS, and NRAS were analysed with Sanger sequencing method, and 1p/19q codeletion was analysed with multiplex ligation-dependent probe amplification. DNA methylation array was performed in some RAS mutant tumours to improve accuracy of diagnosis. RESULTS: RAS mutations were identified in four gliomas with three KRAS mutations and one NRAS mutation in one anaplastic oligodendroglioma, two anaplastic astrocytomas (IDH wild-type in each), and one ganglioglioma. RAS-mutant gliomas were identified with various types of glioma histology. CONCLUSION: RAS mutation appears infrequent, and it is not associated with any specific histological phenotype of glioma.

Role of thyroid hormone-integrin αvß3-signal and therapeutic strategies in colorectal cancers.

Thyroid hormone analogues-particularly, L-thyroxine (T4) has been shown to be relevant to the functions of a variety of cancers. Integrin αvß3 is a plasma membrane structural protein linked to signal transduction pathways that are critical to cancer cell proliferation and metastasis. Thyroid hormones, T4 and to a less extend T3 bind cell surface integrin αvß3, to stimulate the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway to stimulate cancer cell growth. Thyroid hormone analogues also engage in crosstalk with the epidermal growth factor receptor (EGFR)-Ras pathway. EGFR signal generation and, downstream, transduction of Ras/Raf pathway signals contribute importantly to tumor cell progression. Mutated Ras oncogenes contribute to chemoresistance in colorectal carcinoma (CRC); chemoresistance may depend in part on the activity of ERK1/2 pathway. In this review, we evaluate the contribution of thyroxine interacting with integrin αvß3 and crosstalking with EGFR/Ras signaling pathway non-genomically in CRC proliferation. Tetraiodothyroacetic acid (tetrac), the deaminated analogue of T4, and its nano-derivative, NDAT, have anticancer functions, with effectiveness against CRC and other tumors. In Ras-mutant CRC cells, tetrac derivatives may overcome chemoresistance to other drugs via actions initiated at integrin αvß3 and involving, downstream, the EGFR-Ras signaling pathways.

Pathologic Features Associated With Molecular Subtypes of Well-Differentiated Thyroid Cancer.

OBJECTIVE: To determine the association between pathologic features and molecular classes (BRAF-like, RAS-like, and non-BRAF-like non-RAS-like [NBNR]). METHODS: Retrospective review of a merged database containing 676 patients, 84% (571/676) were assigned to a molecular class from publicly accessible sequenced data of thyroid neoplasms. RESULTS: The merged cohort included 571 neoplasms: 353 (62%) BRAF-like, 172 (30%) RAS-like, and 46 (8.1%) NBNR. Lymph node metastasis (any N1 disease) was present in 166/337 (49%) of BRAF-like, 23/164 (14%) of RAS-like, and 0/46 (0%) of NBNR and are significantly different (P < .001). Gross extra-thyroidal extension was observed in 27 patients, including 24/331 (7%) of BRAF-like, 2/160 (1%) of RAS-like, and 1/46 (2%) of NBNR (P = .01). N1B lymph node metastases or T4 disease was present in 74/333 (22%) of BRAF-like, 10/160 (6%) of RAS-like, and 1/46 (2%) of NBNR (P < .0001). Distant metastasis was present in 4/151 (2.6%) of BRAF-like, 2/50 (4%) of RAS-like and 0/46 for NBNR (P = .627). Angioinvasion was present in 0/81 (0%) of BRAF-like, 3/53 (6%) of RAS-like, and 3/46 (7%) of NBNR (P = .08); and multifocality was present in 27/81 (33%) of BRAF-like, 9/53 (17%) of RAS-like, and 1/46 (2%) for NBNR (P = .0001). CONCLUSION: Pathological features of metastasis, gross extra-thyroidal extension, and multifocality were more prevalent in BRAF-like samples compared to RAS-like and NBNR. A trend towards increased frequency of angioinvasion in RAS-like and NBNR cancers compared to BRAF-like samples was observed. Further studies are needed to evaluate if preoperative knowledge of molecular mutations in thyroid tumors aids in decision-making regarding extent of surgery.

Oncogenic NRAS Accelerates Rhabdomyosarcoma Formation When Occurring within a Specific Time Frame during Tumor Development in Mice.

In the Ptch+/- mouse model for embryonal rhabdomyosarcoma (ERMS), we recently showed that oncogenic (onc) H-, K- or NRAS mutations do not influence tumor growth when induced at the advanced, full-blown tumor stage. However, when induced at the invisible ERMS precursor stage at 4 weeks of age, tumor development was enforced upon oncHRAS and oncKRAS but not by oncNRAS, which instead initiated tumor differentiation. These data indicate that oncRAS-associated processes differ from each other in dependency on the isoform and their occurrence during tumor development. Here, we investigated the outcome of oncNRAS induction at an earlier ERMS precursor stage at 2 weeks of age. In this setting, oncNRAS accelerates tumor growth because it significantly shortens the ERMS-free survival and increases the ERMS incidence. However, it does not seem to alter the differentiation of the tumors. It is also not involved in tumor initiation. Together, these data show that oncNRAS mutations can accelerate tumor growth when targeting immature ERMS precursors within a specific time window, in which the precursors are permissive to the mutation and show that oncNRAS-associated processes differ from each other in dependency on their occurrence during tumor development.

The Role of K-Ras and P53 in Biliary Tract Carcinoma.

OBJECTIVE: To focus mainly on the role of proto-oncogene Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (K-Ras) and tumour-suppressor gene p53 which are among the most commonly mutated genes in biliary tract carcinomas. METHODS: The systematic review comprised research articles published between 2002 and 2019 on PubMed and Google Scholar databases which were searched using the terms 'TP53', 'K-Ras', 'mutation', 'biliary tract carcinoma', 'cholangiocarcinoma', and 'murine model'. Repetitions, duplicates and irrelevant articles were excluded. No data was retrieved from posters, presentations and symposiums, and experiments involving bile aspirations were also excluded. RESULTS: Of the 72 articles reviewed, 11(15.3%) were included. Of them, 3(27.3%) studies, conducted in China, Japan and Taiwan, reported a positive correlation between K-Ras mutation and biliary tract carcinoma. Only 1(9%) study, conducted in China, showed the sole correlation between p53 inactivation and biliary tract carcinoma. Also, 4(36.4%) studies, conducted in China, Japan and Europe, showed a positive association of both K-Ras mutation and p53 inactivation with biliary tract carcinoma. CONCLUSIONS: K-Ras and p53 mutation both contribute to biliary tract carcinoma. K-Ras mutation, however, has a much higher frequency compared to p53 inactivation in such cancers.

Type of TP53 mutation influences oncogenic potential and spectrum of associated K-ras mutations in lung-specific transgenic mice.

TP53 and K-ras mutations are two of the major genetic alterations in human nonsmall cell lung cancers. The association between these two genes during lung tumorigenesis is unknown. We evaluated the potential of two common Type I (273H, contact) and Type II (175H, conformational) TP53 mutations to induce lung tumors in transgenic mice, as well as K-ras status, and other driver mutations in these tumors. Among 516 (138 nontransgenic, 207 SPC-TP53-273H, 171 SPC-TP53-175H) mice analyzed, 91 tumors, all adenocarcinomas, were observed. Type II mutants developed tumors more frequently (as compared to nontransgenics, p = 0.0003; and Type I, p = 0.010), and had an earlier tumor onset compared to Type I (p = 0.012). K-ras mutations occurred in 21 of 50 (42%) of murine lung tumors sequenced. For both the nontransgenic and the SPC-TP53-273H transgenics, tumor K-ras codon 12-13 mutations occurred after 13 months with a peak incidence at 16-18 months. However, for the SPC-TP53-175H transgenics, K-ras codon 12-13 mutations were observed as early as 6 months, with a peak incidence between the ages of 10-12 months. Codons 12-13 transversion mutations were the predominant changes in the SPC-TP53-175H transgenics, whereas codon 61 transition mutations were more common in the SPC-TP53-273H transgenics. The observation of accelerated tumor onset, early appearance and high frequency of K-ras codon 12-13 mutations in the Type II TP53-175H mice suggests an enhanced oncogenic function of conformational TP53 mutations, and gains in early genetic instability for tumors containing these mutations compared to contact mutations.