Successful cetuximab rechallenge in metastatic colorectal cancer: A case report.

BACKGROUND: Metastatic colorectal cancer (mCRC) treatment has been evolving and increasingly driven by tumor biology and gene expression analysis. Rechallenge with epidermal growth factor receptor (EGFR) inhibitors (anti-EGFR) represents a promising strategy for patients with RAS wild-type (RAS-wt) mCRC and circulating tumor DNA has emerged as a potential selection strategy. Herein, we report the case of a RAS-wt mCRC patient who had a successful response to cetuximab rechallenge. CASE SUMMARY: Our patient was diagnosed with stage IV RAS-wt, microsatellite-stable rectosigmoid junction adenocarcinoma. He was started on first-line treatment with FOLFIRI and cetuximab and achieved partial response, allowing for a left hepatectomy (R0), followed by post-operative chemotherapy and an anterior resection; progression-free survival (PFS) of 16 months was obtained. Due to hepatic and nodal relapse, second-line treatment with FOLFOX and bevacizumab was started with partial response; metastasectomy was performed (R0), achieving a PFS of 11 months. After a 15 months anti-EGFR-free interval, FOLFIRI and cetuximab were reintroduced upon disease progression, again with partial response and a PFS of 16 months. Following extensive hepatic relapse, cetuximab was reintroduced and a marked clinical and analytical improvement was seen, after only one cycle. RAS-wt status was confirmed on circulating tumor DNA. The patient's overall survival exceeded 5 years. CONCLUSION: Our case provides real-world data to support cetuximab rechallenge in later lines of RAS-wt mCRC treatment.

The survival outcome differs between left-sided colon cancer and middle/low rectal cancer after colorectal hepatic metastasectomy.

BACKGROUND: The clinical outcomes between left-sided colon cancer and middle/low rectal cancer seem to be different. This study aimed to examine the effect of primary tumor location regarding the left-sided colon and middle/low rectum on the overall survival (OS) of patients who underwent colorectal hepatic metastasectomy. METHODS: Patients who underwent colorectal hepatic metastasectomy were retrospectively enrolled. Patients were classified into 2 groups according to the primary tumor location (left-sided colon and middle/low rectum). Categorical variables were compared using the chi-square test or Fisher exact test, and continuous variables were analyzed using the Student t test. Survival was analyzed using the Kaplan-Meier method and log-rank test. The prognostic factors were analyzed by univariate and multivariate analyses using Cox proportional hazards regression models. RESULTS: Overall, 365 patients were enrolled. Patients with left-sided colon cancer had significantly better OS than those with middle/low rectal cancer (hazard ratio [HR], 0.725; P = .018), with median OS estimates of 48 and 38 months, respectively. In the subgroup analysis of RAS mutations, patients with left-sided colon cancer had significantly prolonged OS compared with those with middle/low rectum cancer (HR, 0.608; P = .034), with median OS estimates of 49 and 26 months, respectively. This observation was limited to patients with RAS mutations. CONCLUSION: According to our findings, patients with middle/low rectal cancer had poorer survival outcome and should not be categorized together with patients with left-sided colon cancer in terms of OS after colorectal hepatic metastasectomy.

Molecular Pathology of Thyroid Tumors: Old Problems and New Concepts.

The molecular signatures of many thyroid tumors have been uncovered. These discoveries have translated into clinical practice and are changing diagnostic and tumor classification paradigms. Here, the findings of recent studies are presented with special emphasis on how molecular insights are impacting the understating of RAS mutant thyroid nodules, Hürthel cell neoplasms, and unusual thyroid tumors, such as hyalinizing trabecular tumor, secretory carcinoma of the thyroid, and sclerosing mucoepidermoid carcinoma with eosinophilia. In addition, the utility of detecting actionable molecular alterations by immunohistochemistry in advanced and aggressive thyroid cancer is also discussed.

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.

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.

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.

Unmasking the Silent Invader: A Rare Case of Follicular Thyroid Carcinoma With Skull Metastasis and an Uncommon KRAS Q61R Mutation.

Follicular thyroid carcinoma (FTC) is a noteworthy subtype of thyroid cancer known for its tendency to metastasize through the bloodstream, usually to the lungs and bones. This case report examines an exceptionally rare instance involving an 81-year-old female presenting with an unusual metastatic scalp lesion. Remarkably, this aggressive metastasis originated from a thyroid lesion as small as 0.7 cm. Lab findings, including suppressed TSH and elevated T3 levels, revealed subclinical hyperthyroidism, adding another layer of rarity to this FTC case. Molecular profiling identified a rare KRAS Q61R mutation, providing potential insight into the case's aggressive behavior and underscoring the importance of genetic assessment in FTC. This report emphasizes the critical role of comprehensive diagnostic evaluations, including histopathological assessments, in properly diagnosing and managing FTC, especially when clinical presentations defy conventional paradigms.

Developing Models to Predict BRAFV600E and RAS Mutational Status in Papillary Thyroid Carcinoma Using Clinicopathological Features and pERK1/2 Immunohistochemistry Expression.

The Cancer Genome Atlas (TCGA) has classified papillary thyroid carcinoma (PTC) into indolent RAS-like and aggressive BRAF-like based on its distinct driver gene mutations. This retrospective study aimed to assess clinicopathology and pERK1/2 expression variations between BRAF-like and RAS-like PTCs and establish predictive models for BRAFV600E and RAS-mutated PTCs. A total of 222 PTCs underwent immunohistochemistry staining to assess pERK1/2 expression and Sanger sequencing to analyze the BRAF and RAS genes. Multivariate logistic regression was employed to develop prediction models. Independent predictors of the BRAFV600E mutation include a nuclear score of 3, the absence of capsules, an aggressive histology subtype, and pERK1/2 levels exceeding 10% (X2 = 0.128, p > 0.05, AUC = 0.734, p < 0.001). The RAS mutation predictive model includes follicular histology subtype and pERK1/2 expression > 10% (X2 = 0.174, p > 0.05, AUC = 0.8, p < 0.001). We propose using the prediction model concurrently with four potential combination group outcomes. PTC cases included in a combination of the low-BRAFV600E-scoring group and high-RAS-scoring group are categorized as RAS-like (adjOR = 4.857, p = 0.01, 95% CI = 1.470-16.049). PTCs included in a combination of the high-BRAFV600E-scoring group and low-RAS-scoring group are categorized as BRAF-like PTCs (adjOR = 3.091, p = 0.001, 95% CI = 1.594-5.995). The different prediction models indicate variations in biological behavior between BRAF-like and RAS-like PTCs.

DUSP1 Signaling Pathway Regulates Cytarabine Sensitivity in Acute Myeloid Leukemia.

Objectives: Dual specificity phosphatase 1 (DUSP1) is high-expressed in various cancers and plays an important role in the cellular response to agents that damage DNA. We aimed to investigate the expressions and mechanisms of DUSP1 signaling pathway regulating cytarabine (Ara-C) resistance in acute myeloid leukemia (AML). Methods: Immunohistochemistry was performed on bone marrow biopsy specimens from AML and controls to explore the expression of DUSP1. Western blot and Q-PCR were used to detect the protein and mRNA expression levels. MTT assay was used to detect the proliferation of cells. Cell apoptosis was detected by flow cytometry. The immune protein-protein interaction (PPI) network of DUSP1 was analyzed in the platform of Pathway Commons, and immune infiltration analysis was used to study the immune microenvironment of AML. Results: We found that the expression levels of DUSP1 in AML patients exceeded that in controls. Survival analysis in public datasets showed that AML patients with higher levels of DUSP1 had poor clinical outcomes. Further public data analysis indicated that DUSP1 was overexpressed in NRAS mutated AML. DUSP1 knockdown by siRNA could sensitize AML cells to Ara-C treatments. The phosphorylation level of mitogen-activated protein kinase (MAPK) pathway was significantly elevated in DUSP1 down-regulated NRAS G13D mutated AML cells. The PPI analysis showed DUSP1 correlated with immune gene CREB1 and CXCL8 in NRAS mutated AML. We also revealed a correlation between tumor-infiltrating immune cells in RAS mutated AML microenvironment. Conclusion: Our findings suggest that DUSP1 signaling pathways may regulate Ara-C sensitivity in AML.

Time to recurrence and its relation to survival after recurrence in patients resected for stage III colon cancer.

BACKGROUND: It is intuitively thought that early relapse is associated with poor survival after recurrence (SAR) in resected colon cancer (CC) patients, but this has never been formally studied. METHODS: We pooled data from stage III patients treated with oxaliplatin-based adjuvant therapy in two phase III trials, to analyse time to recurrence (TTR) and its relationship with SAR. TTR and SAR were also studied according to molecular status (mismatch repair (MMR), RAS, and BRAFV600E). Early relapsing patients were defined as patients having a TTR event within 12 months after starting adjuvant chemotherapy. RESULTS: 4548 stage III CC patients were included in the present analysis. Deficient MMR (dMMR) CC patients experienced fewer recurrences than proficient (p)MMR CC patients (18.8% versus 27.6%) but had a significantly shorter median TTR (mTTR; 0.74 versus 1.40 years, p < 0.0001). In pMMR patients, BRAF and RAS mutations were also associated with earlier mTTR as compared to double wild-type (WT) patients (0.99 versus 1.38 versus 1.54 years, respectively, p < 0.0001). Early recurrence occurred in 397 patients and was associated with a median SAR (2.2 versus 3.3 years, p = 0.0007). However, this association was mainly due to pMMR/RAS and BRAFV600E mutated tumours and was not confirmed in dMMR and pMMR/double WT subgroups. CONCLUSION: In resected stage III CC treated with standard oxaliplatin-based adjuvant therapy, TTR varies between dMMR, pMMR/RAS, or BRAFV600E mutated and pMMR/double WT tumours. In addition, early relapse is associated with poor survival, mainly due to patients resected for a pMMR/RAS or BRAFV600E mutated tumour.

Small molecular inhibitors for KRAS-mutant cancers.

Three rat sarcoma (RAS) gene isoforms, KRAS, NRAS, and HRAS, constitute the most mutated family of small GTPases in cancer. While the development of targeted immunotherapies has led to a substantial improvement in the overall survival of patients with non-KRAS-mutant cancer, patients with RAS-mutant cancers have an overall poorer prognosis owing to the high aggressiveness of RAS-mutant tumors. KRAS mutations are strongly implicated in lung, pancreatic, and colorectal cancers. However, RAS mutations exhibit diverse patterns of isoforms, substitutions, and positions in different types of cancers. Despite being considered "undruggable", recent advances in the use of allele-specific covalent inhibitors against the most common mutant form of RAS in non-small-cell lung cancer have led to the development of effective pharmacological interventions against RAS-mutant cancer. Sotorasib (AMG510) has been approved by the FDA as a second-line treatment for patients with KRAS-G12C mutant NSCLC who have received at least one prior systemic therapy. Other KRAS inhibitors are on the way to block KRAS-mutant cancers. In this review, we summarize the progress and promise of small-molecule inhibitors in clinical trials, including direct inhibitors of KRAS, pan-RAS inhibitors, inhibitors of RAS effector signaling, and immune checkpoint inhibitors or combinations with RAS inhibitors, to improve the prognosis of tumors with RAS mutations.

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.

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.

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.

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).

Sintilimab plus bevacizumab, oxaliplatin and capecitabine as first-line therapy in RAS-mutant, microsatellite stable, unresectable metastatic colorectal cancer: an open-label, single-arm, phase II trial.

Background: Microsatellite stable (MSS) and RAS-mutant metastatic colorectal cancer (mCRC) patients are characterized by an immunosuppressive microenvironment and a low response rate to immunotherapy. Chemotherapy and anti-angiogenesis therapy have been reported to potentially promote immunotherapy response. This study aims to assess the preliminary anti-tumor activity and safety of sintilimab plus bevacizumab, oxaliplatin and capecitabine as a treatment option for patients with RAS-mutant MSS mCRC. Methods: This study was an open-label, single-arm, phase II trial in China. Patients with unresectable, RAS-mutant and MSS metastatic colorectal adenocarcinoma received treatment by intravenous sintilimab (200 mg, day 1) plus bevacizumab (7.5 mg/kg, day 1), oxaliplatin (135 mg/m2, day 1) and oral capecitabine (1 g/m2, day 1-14) in each 21-day cycle. The primary endpoints included objective response rate (ORR) and adverse events. Biomarker analysis was performed to identify potential predictors of good response to treatment. This study is registered with ClinicalTrials.gov, number NCT04194359. Findings: Between April 2021 and December 2021, 25 patients were enrolled. Two (8%) patients showed complete response (CR), 19 (76%) had partial response (PR) and 4 (16%) presented with stable disease. ORR reached 84% (95% CI, 63.9-95.5) and the disease control rate was 100% (95% CI, 86.3-100). The median progression-free survival (PFS) was 18.2 months for the full analysis set. The most common treatment-related adverse events (TRAEs) in all grades were anemia (21/25, 84%), neutropenia (20/25, 80%), and hand-foot syndrome (14/25, 56%). The most frequent grade 3 or 4 TRAEs were neutropenia (3/25, 12%) and increased alanine transaminase (2/25, 8%). No grade 5 adverse events occurred. In the exploration of biomarkers, 5 patients could be characterized as TTN/OBSCN "double-hit" after treatment, and the copy number variants burden was significantly decreased in tumor tissues after treatment compared with the baseline. Nanostring panel RNA sequencing analysis indicated a better tumor immune microenvironment cell infiltration in CR/PR patients compared with non-CR/PR patients as well as the PFS-long (≥12.5 months) group compared with the PFS-short group. Interpretation: Combination treatment with sintilimab plus bevacizumab, oxaliplatin and capecitabine as first-line treatment demonstrated a promising antitumor activity and a manageable safety profile in RAS-mutant, MSS and unresectable mCRC. Exploratory biomarker assessment analysis showed that some RAS-mutant and MSS patients changed into "immune-hot" subtype after the treatment. Funding: This study was supported by the Key R&D Program of Zhejiang Province (2021C03125 to Ying Yuan), the National Natural Science Foundation of China (81872481 to Ying Yuan, 82072624 to Kefeng Ding), the Fundamental Research Funds for the Central Universities (No. 226-2022-00009 to Kefeng Ding), and the Zhejiang Provincial Natural Science Foundation of China (No. LY22H160024 to Hanguang Hu).

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.

Treatment Outcomes of Sofosbuvir/Velpatasvir/Voxilaprevir in Direct-Acting Antiviral-Experienced Hepatitis C Virus Patients: A Systematic Review and Meta-Analysis.

About 5% of chronic hepatitis C (CHC) patients experienced treatment failure with direct-acting antiviral (DAA) treatment. The global data on the practice and treatment outcomes of Sofosbuvir/Velpatasvir/Voxilaprevir (SOF/VEL/VOX) in DAA-experienced CHC patients remains sparse. We performed a systematic review and meta-analysis to evaluate the efficacy and safety of SOF/VEL/VOX as a salvage treatment in DAA-experienced CHC patients. We searched five electronic databases from inception to 31 January 2023. The study outcomes were SVR12 and treatment-related adverse effects, with subgroup analysis performed based on genotype, cirrhosis, HCC, prior SOF/VEL exposure, and region. We identified and analyzed data from 24 studies (2877 DAA-experienced CHC patients); 17.2% had prior SOF/VEL exposure, 25% received ribavirin with SOF/VEL/VOX, and 42% had pre-treatment resistance-associated substitution (RAS) testing performed. Eastern Mediterranean had a higher pooled SVR12 than the America and Europe regions (p < 0.05). Predictors of SOF/VEL/VOX failure were genotype 3, active HCC, baseline cirrhosis, and prior SOF/VEL. Baseline RAS mutation and ribavirin supplementation were not associated with higher SVR12. Treatment discontinuation because of drug-related adverse events was uncommon (10 studies, 0.2%). In summary, SOF/VEL/VOX is efficacious and safe for retreatment in DAA-experienced CHC patients, even with RAS mutation. Our findings support SOF/VEL/VOX as a first-line rescue treatment for DAA-experienced CHC patients.

Simultaneous p53 and KRAS mutation in a high-grade serous carcinoma with deceptive appearance of a low-grade carcinoma. A case report.

Low-grade and high-grade serous carcinomas have unique clinical, morphological, underlying molecular alterations, and vastly different biologic behavior (Prat et al., 2018, Vang et al., 2009). The differentiation into high and low-grade serous carcinoma is important for clinical management and prognosis and is easily recognized by practicing pathologists. High-grade serous carcinoma is characterized by marked nuclear atypia and pleomorphism, frequent, often atypical mitosis with papillary or three-dimensional clusters, p53 mutation, and block-like p16 staining. In contrast, low-grade serous carcinomas have a different morphologic appearance with micropapillary formation, small nests of tumor cells having low to intermediate grade nuclei, and absence of significant mitosis. Low-grade serous carcinoma is often associated with micropapillary variant of ovarian serous borderline tumor. The low-grade serous carcinoma shows wild type p53 expression, patchy p16 staining, and often K-RAS, N-RAS, and/or B-RAF mutation. Here we report a case of mullerian high grade serous with a deceptive morphology resembling low-grade serous carcinoma with micropapillary features and moderate nuclear atypia. However, the tumor is simultaneously p53 and K-RAS mutated. This case illustrates three critical issues; a) potential to be mistaken as a low-grade serous carcinoma because of morphologic appearance and relative uniform cytologic feature. b). raise the question of true progression of low-grade to high-grade serous carcinoma, a rare phenomenon as described in the literature, and c). whether the biologic behavior and/or response to therapy would differ from the classic forms.