Favorable outcome of immunotherapy in a rare subtype of hepatocellular carcinoma: a case report and literature review.

Scirrhous hepatocellular carcinoma (S-HCC) represents an uncommon subtype of HCC. During radiological evaluation this unique subtype is frequently mistaken as cholangiocarcinoma, fibrolamellar HCC, or metastatic adenocarcinoma. Here, we present the case of a 50-year-old woman with a large hepatic mass. A triple-phase computed tomography of the liver revealed an arterial enhancing lesion without portovenous washout at hepatic segment 4a/8. The liver biopsy showed hepatocellular characteristics and was positive for Hep Par 1, CK7, CK19, Arginase 1 and CEA, indicating atypical S-HCC. This patient had achieved tumor control with combined treatment with atezolizumab plus bevacizumab and was then treated with lenvatinib after tumor progression. The patient died 15 months after the initial diagnosis.

Cost-Utility and Budget Impact Analyses of Oral Chemotherapy for Stage III Colorectal Cancer: Real-World Evidence after Policy Implementation in Thailand.

This study conducted a cost-utility analysis and a budget impact analysis (BIA) of outpatient oral chemotherapy versus inpatient intravenous chemotherapy for stage III colorectal cancer (CRC) in Thailand. A Markov model was constructed to estimate the lifetime cost and health outcomes based on a societal perspective. Eight chemotherapy strategies were compared. Clinical and cost data on adjuvant chemotherapy were collected from the medical records of 1747 patients at Siriraj Hospital, Thailand. The cost-effectiveness results were interpreted against a Thai willingness-to-pay threshold of USD 5003/quality-adjusted life year (QALY) gained. A 5-year BIA was performed. Of the eight strategies, CAPOX then FOLFIRI yielded the highest life-year and QALY gains. Its total lifetime cost was also the highest. An incremental cost-effectiveness ratio of CAPOX then FOLFIRI compared to 5FU/LV then FOLFOX, a commonly used regimen USD was 4258 per QALY gained.The BIA showed that when generic drug prices were applied, 5-FU/LV then FOLFOX had the smallest budgetary impact (USD 9.1 million). CAPOX then FOLFIRI required an approximately three times higher budgetary level (USD 25.1 million). CAPOX then FOLFIRI is the best option. It is cost-effective compared with 5-FU/LV then FOLFOX. However, policymakers should consider the relatively high budgetary burden of the CAPOX then FOLFIRI regimen.

The KRAS-Mutant Consensus Molecular Subtype 3 Reveals an Immunosuppressive Tumor Microenvironment in Colorectal Cancer.

Colorectal cancers (CRC) with KRAS mutations (KRASmut) are frequently included in consensus molecular subtype 3 (CMS3) with profound metabolic deregulation. We explored the transcriptomic impact of KRASmut, focusing on the tumor microenvironment (TME) and pathways beyond metabolic deregulation. The status of KRASmut in patients with CRC was investigated and overall survival (OS) was compared with wild-type KRAS (KRASwt). Next, we identified CMS, and further investigated differentially expressed genes (DEG) of KRASmut and distinctive pathways. Lastly, we used spatially resolved gene expression profiling to define the effect of KRASmut in the TME regions of CMS3-classified CRC tissues. CRC patients with KRASmut were mainly enriched in CMS3. Their specific enrichments of immune gene signatures in immunosuppressive TME were associated with worse OS. Activation of TGFß signaling by KRASmut was related to reduced pro-inflammatory and cytokine gene signatures, leading to suppression of immune infiltration. Digital spatial profiling in TME regions of KRASmut CMS3-classified tissues suggested up-regulated genes, CD40, CTLA4, ARG1, STAT3, IDO, and CD274, that could be characteristic of immune suppression in TME. This study may help to depict the complex transcriptomic profile of KRASmut in immunosuppressive TME. Future studies and clinical trials in CRC patients with KRASmut should consider these transcriptional landscapes.

Combining the SMAC mimetic LCL161 with Gemcitabine plus Cisplatin therapy inhibits and prevents the emergence of multidrug resistance in cholangiocarcinoma.

Cholangiocarcinoma (CCA) is a highly lethal gastrointestinal malignancy that has one of the worst prognoses among solid tumors. The combination of Gemcitabine + Cisplatin (GEM/CIS) remains the standard first-line treatment for advanced stage CCA. However, this drug combination yields only a modest objective response rate, and in cases that initially respond to this treatment, drug resistance commonly rapidly develops. To improve the efficiency of GEM/CIS therapy for CCA, a thorough understanding of the mechanism of GEM/CIS resistance in CCA is required. To that end - in this study, we developed several acquired GEM/CIS-resistant CCA cell lines and we screened those cell lines for acquired vulnerability. The screening process revealed that subset of CCA with GEM/CIS resistance acquired vulnerability to the small-molecule second mitochondrial-derived activator of caspases (SMAC) mimetics LCL161 and Birinapant. The observed acquired vulnerability was found to be associated with upregulation of an inhibitor of apoptosis protein 2 (cIAP2), a known target of SMAC mimetics. LCL161 or cIAP2-shRNA downregulated cIAP2 and restored the sensitivity to GEM/CIS in GEM/CIS-resistant CCA cell lines and in in vivo GEM/CIS-resistant xenograft models. A strong synergic effect was observed when LCL161 was added to GEM/CIS. Interestingly, this synergism was also observed in drug-naïve CCA cell lines, xenografts, and patient-derived organoids. This triplet therapy also prevented the emergence of multidrug-resistant CCA in in vitro and in vivo models. Our findings suggest that activation of cIAP2 allows CCA to escape GEM/CIS, and that suppression of cIAP2 reestablishes the apoptotic profile of CCA, thus restoring its vulnerability to GEM/CIS. The results of this study indicate that combining the SMAC mimetic LCL161 with GEM/CIS inhibits and prevents the emergence of multidrug resistance in CCA.

Efficacy, Safety, and Patient-Reported Outcomes of Atezolizumab Plus Bevacizumab for Unresectable Hepatocellular Carcinoma in Thailand: A Multicenter Prospective Study.

PURPOSE: Atezolizumab plus bevacizumab treatment is a first-line therapy for unresectable hepatocellular carcinoma (HCC) worldwide. The efficacy, safety, and patient-reported outcomes (PROs) of HCC in Thailand have not yet been reported. This study aimed to evaluate the efficacy, safety, and PROs of atezolizumab plus bevacizumab. MATERIALS AND METHODS: From September 2020 to August 2021, 30 patients with unresectable HCC who met the inclusion criteria of atezolizumab plus bevacizumab as first-line treatment were enrolled. Analysis was assessed for progression-free survival, overall survival, adverse events (AEs), and quality of life (QoL). RESULTS: The median progression-free survival and overall survival periods were 6.7 and 10.2 months, respectively. The disease control rate was 63.3%. The frequent AEs were proteinuria, hypertension, and hepatitis. Serious AEs included gastrointestinal bleeding, but none of the patients died from serious AEs. The discontinuation rate was 23.3%, and the median number of treatment cycles was 10.5 cycles. In total, 23.3% of the patients continued treatment after 1 year of therapy. The global health status/QoL and physical function scores showed less deterioration at baseline than at 3 and 6 months (median scores = 76.7, 71.6, and 64.1 in QoL and 84.7, 79.6, and 79.0 in physical function, respectively). The HCC18 symptom score index data showed a slow progression of symptom scores from baseline to 3 and 6 months (12.7, 19.6, and 22.3, respectively). CONCLUSION: This study demonstrates that atezolizumab plus bevacizumab is effective and has a safety profile comparable with that of previous studies as first-line therapy for unresectable HCC in a real-world setting and in Thai populations. Data on PROs also demonstrate benefits in terms of patients' QoL and symptoms.

Primary pulmonary lymphoepithelioma-like carcinoma treated with immunotherapy: A case report and literature review.

Here, we report a case of metastatic Epstein-Barr virus (EBV)-related primary pulmonary lymphoepithelioma-like carcinoma (PPLELC) in a young, nonsmoking female who responded well to treatment with two types of immune checkpoint inhibitors (ICIs). This is the first case report of a favorable outcome to ICIs in the late-line treatment of advanced PPLELC patients with programmed cell death-ligand 1 (PD-L1) expression.

Low Fat-Free Mass Index Measured by Bioelectrical Impedance Analysis Correlates With Hematologic Adverse Events in Early-Stage Breast Cancer Patients Receiving Chemotherapy: A Prospective Observational Cohort Study.

Background: Low muscle mass is associated with worse cancer treatment outcomes. Although dual-energy X-ray absorptiometry or computerized tomography-based analysis have both been widely studied in this clinical setting, studies in the use of bioelectrical impedance analysis (BIA) remain limited. The aim of this prospective study was to investigate for association between body composition estimated by BIA and hematologic adverse events in early-stage breast cancer patients receiving chemotherapy. Methods: A total of 144 female patients were enrolled. Before the first cycle of chemotherapy, body weight and fat-free mass were measured by a BIA device and then those values were converted into body mass index and fat-free mass index. Association between fat-free mass index and composite adverse events (CAEs), including grade 4 neutropenia, febrile neutropenia, or relative dose intensity <85%, was explored. Results: CAEs occurred in 85 patients (59%), and point biserial correlation showed an inverse correlation between the fat-free mass index and CAE. No included patients were sarcopenic (fat-free mass index <11.4 kg/m2). Receiver operating characteristic curve analysis revealed <14.85 kg/m2 as the cutoff value indicating a low fat-free mass index. Using this cutoff, 85 patients were classified as having a low fat-free mass index, and 62 of those patients (72.9%) had CAE (relative risk: 1.86, P < .001). After adjusting for other factors, a low fat-free mass index was found to be independently associated with a high CAE (adjusted odds ratio: 4.562, 95% CI: 2.162-9.627, P < .001). Conclusion: Low fat-free mass index is an independent predictor of increased risk of hematologic adverse events in early-stage breast cancer patients receiving chemotherapy. Estimation of fat-free mass index by BIA may identify at-risk patients so that interventions can be considered to improve treatment outcomes.

The Acquired Vulnerability Caused by CDK4/6 Inhibition Promotes Drug Synergism Between Oxaliplatin and Palbociclib in Cholangiocarcinoma.

Cholangiocarcinoma (CCA) is one of the most difficult to treat cancers, and its nature of being largely refractory to most, if not all, current treatments results in generally poor prognosis and high mortality. Efficacious alternative therapies that can be used ubiquitously are urgently needed. Using acquired vulnerability screening, we observed that CCA cells that reprofile and proliferate under CDK4/6 inhibition became vulnerable to ribosomal biogenesis stress and hypersensitive to the anti-ribosome chemotherapy oxaliplatin. CCA cells overexpress the oncogenic ribosomal protein RPL29 under CDK4/6 inhibition in a manner that correlated with CDK4/6 inhibitor resistance. Depletion of RPL29 by small interfering RNAs (siRNAs) restored the sensitivity of CCA cells to CDK4/6 inhibition. Oxaliplatin treatment suppressed the RPL29 expression in the CDK4/6 inhibitor treated CCA cells and triggered RPL5/11-MDM2-dependent p53 activation and cancer apoptosis. In addition, we found that combination treatment with oxaliplatin and the CDK4/6 inhibitor palbociclib synergistically inhibited both parental and CDK4/6 inhibitor-resistant CCA, and prevented the emergence of CDK4/6 and oxaliplatin-resistant CCA. This drug combination also exerted suppressive and apoptosis effects on CCA in the in vitro 3-dimensional culture, patient-derived organoid, and in vivo xenograft CCA models. These results suggest the combination of the CDK4/6 inhibitor palbociclib and the anti-ribosome drug oxaliplatin as a potentially promising treatment for cholangiocarcinoma.

Effect of Primary Tumor Location on Second- or Later-Line Treatment With Anti-Epidermal Growth Factor Receptor Antibodies in Patients With Metastatic Colorectal Cancer: A Retrospective Multi-Center Study.

BACKGROUND: Current guidelines recommend anti-epidermal growth factor receptor monoclonal antibodies (anti-EGFR Ab) as first-line treatment only in patients with left-sided RAS wild type (RASwt) metastatic colorectal cancer (mCRC). However, there are no guideline recommendations specific to tumor sidedness in subsequent-line treatment. This study aimed to investigate the effect of primary tumor location on second- or later-line treatment outcomes in patients with KRASwt mCRC. METHODS: Medical records of patients diagnosed with mCRC at 3 academic centers in Thailand (Siriraj, Chulalongkorn, and Ramathibodi hospital) between 2008 and 2019 were retrospectively reviewed. Patients with KRASwt mCRC who received anti-EGFR Ab in second- or later-line treatment were included. The impact of tumor sidedness on progression-free survival (PFS) was determined using Kaplan-Meier method, and those results were compared using log-rank test. RESULTS: Among the 2,102 patients who had KRAS analysis data, 1,130 (54%) patients had KRASwt. Of those, 413 patients received anti-EGFR Ab in second- or later-line treatment. One hundred and sixty-two of 413 (39%) patients had extended RAS analysis. Seventy (17%) patients had right-sided tumors. Two hundred and thirty-eight (58%) patients received anti-EGFR Ab in the third line, and 132 (32%) patients and 43 (10%) patients were treated in the second and more than third line, respectively. Single-agent irinotecan was the most commonly used backbone chemotherapy (303/413, 73%). Patients with right-sided tumors had non-significantly inferior PFS compared to patients with left-sided tumors (median PFS: 5.7 months (mo), 95% confidence interval [CI]: 3.9-7.5 vs. 7.5 mo, 95% CI 6.5-8.5; p=0.17). Subgroup analysis showed no difference in PFS when stratified by treatment lines. Patient with right-sided tumors had significantly inferior OS compared to patients with left-sided tumors (median OS: 23.3 mo vs. 29.9 mo; p=0.005). CONCLUSIONS: To date, this is the largest real world data of the effect of primary tumor location on anti-EGFR Ab which demonstrated that tumor sidedness has no significant impact on treatment outcomes in KRASwt mCRC patients receiving second- or later-line therapy. Our findings do not support the utility of tumor sidedness for treatment selection in these settings. We confirmed that patients with right-sided tumors had significantly worse survival.

Co-occurrence CDK4/6 amplification serves as biomarkers of de novo EGFR TKI resistance in sensitizing EGFR mutation non-small cell lung cancer.

Despite the development of predictive biomarkers to shape treatment paradigms and outcomes, de novo EGFR TKI resistance advanced non-small cell lung cancer (NSCLC) remains an issue of concern. We explored clinical factors in 332 advanced NSCLC who received EGFR TKI and molecular characteristics through 65 whole exome sequencing of various EGFR TKI responses including; de novo (progression within 3 months), intermediate response (IRs) and long-term response (LTRs) (durability > 2 years). Uncommon EGFR mutation subtypes were significantly variable enriched in de novo resistance. The remaining sensitizing EGFR mutation subtypes (exon 19 del and L858R) accounted for 75% of de novo resistance. Genomic landscape analysis was conducted, focusing in 10 frequent oncogenic signaling pathways with functional contributions; cell cycle, Hippo, Myc, Notch, Nrf2, PI-3-Kinase/Akt, RTK-RAS, TGF-ß, p53 and ß-catenin/Wnt signaling. Cell cycle pathway was the only significant alteration pathway among groups with the FDR p-value of 6 × 10-4. We found only significant q-values of < 0.05 in 7 gene alterations; CDK6, CCNE1, CDK4, CCND3, MET, FGFR4 and HRAS which enrich in de novo resistance [range 36-73%] compared to IRs/LTRs [range 4-22%]. Amplification of CDK4/6 was significant in de novo resistance, contrary to IRs and LTRs (91%, 27.9% and 0%, respectively). The presence of co-occurrence CDK4/6 amplification correlated with poor disease outcome with HR of progression-free survival of 3.63 [95% CI 1.80-7.31, p-value < 0.001]. The presence of CDK4/6 amplification in pretreatment specimen serves as a predictive biomarker for de novo resistance in sensitizing EGFR mutation.

Loss of CDX-2 expression is an independent poor prognostic biomarker in patients with early-stage deficient mismatch repair colorectal cancer.

AIM: To investigate the clinicopathological factors, molecular features, and prognostic implications associated with loss of Caudal-related homeobox transcription factor 2 (CDX-2) expression in colorectal cancer (CRC) patients. METHODS: Immunohistochemistry for CDX-2 expression was performed on formalin-fixed, paraffin-embedded primary CRC tissue samples from 449 patients. Correlation between CDX-2 expression and clinicopathological and molecular characteristics was evaluated. Univariate and multivariate survival analyses were performed to determine the prognostic value of loss of CDX-2 expression. RESULTS: Of 449 patients, 84% were stage I-III. CDX-2-negative expression was identified in 18 of 441 (4.1%) patients. Loss of CDX-2 expression was more commonly found in patients with right-sided tumors rather than left-sided tumors (odds ratio [OR] = 3.57; p = 0.009), deficient mismatch repair (dMMR) compared to proficient MMR (pMMR) (OR = 3.7; p = 0.012), and BRAF mutation compared to BRAF wild type (OR = 8.06; p = 0.002). Univariate analysis revealed that stage I-III CRC patients with loss of CDX-2 expression had significantly worse overall survival (OS) and disease-free survival (DFS) than those with positive CDX-2 expression (5-year OS = 33.3% vs. 74.6%, respectively; p < 0.001, and 5-year DFS: 42.9% vs. 69.5%, respectively; p = 0.004). Loss of CDX-2 expression remained significantly associated with worse OS compared to positive CDX-2 expression in multivariate analysis (hazard ratio [HR] = 2.4; 95% confidence interval [CI], 1.12-5.11; p = 0.023). CONCLUSIONS: Loss of CDX-2 expression was found to be associated with right-sided tumor, dMMR status, and BRAF mutation. Moreover, loss of CDX-2 expression is a poor prognostic factor for OS in stage I-III, even among patients with dMMR tumors.

Corrigendum: Combining the SMAC mimetic LCL161 with Gemcitabine plus Cisplatin therapy inhibits and prevents the emergence of multidrug resistance in cholangiocarcinoma.

[This corrects the article DOI: 10.3389/fonc.2022.1021632.].

Efficacy of Combination Docetaxel and Nintedanib in Advanced Non-Small Cell Lung Cancer in Thailand: A Multicenter Study.

INTRODUCTION: The mainstay systemic treatment for non-oncogenic addictive advanced stage non-small cell lung cancer is chemotherapy. Anti-angiogenic agents are additive compounds that enhance disease control and lead to improvement of overall survival benefit. Recently PD-(L)1 blockage, a checkpoint inhibitor, has been adopted as another line of treatment. A sequential strategy to enhance the efficacy of combination docetaxel and nintedanib after immunotherapy, correlated with genomic mutation, has been explored. METHOD: A retrospective cohort study of 56 patients from 8 centers in Thailand who received combination docetaxel and nintedanib via the Thai nintedanib Named Patient Use program was conducted. Demographic characteristics, treatment details, and treatment responses were retrieved from medical records. RESULTS: The majority of patients were male (62.5%) with adenocarcinoma subtype (88%). Thirty-five percent had sensitizing EGFR mutation. Combination docetaxel and nintedanib was given as second to fourth line of treatment. Median PFS of docetaxel/nintedanib was 5.6 months [95% CI 4.8-6.9]. Median OS of the entire cohort was 22.5 months [95% CI 20.2-31.1]. Among them, only four patients received this combination after immunotherapy which limited the validity of efficacy analysis. Median PFS of those four patients was 7.9 months [range 5.2-9.1] which was slightly higher than the remaining cohort (median PFS 4.5 months, 95% CI: 4.0-6.0, p-value 0.09). Among the adenocarcinoma subtype, a relapse-time of platinum-doublet chemotherapy of more than 6 months was solely indicated as a benefit of combination docetaxel/nintedanib treatment compared to the relapse-time of platinum-doublet chemotherapy of less than 6 months by multivariate HR of PFS 0.32 [95% CI: 0.14-0.68, p-value 0.003]. CONCLUSION: Combination docetaxel and nintedanib provided more benefit in relapse-time of platinum-doublet chemotherapy of more than 6 months in advanced stage adenocarcinoma lung cancer. Neither EGFR nor ALK alteration influenced the outcome of treatment.

Clinicopathological Characteristics and Outcome of Adolescent and Young Adult-Onset Microsatellite Stable Colorectal Cancer Patients.

Purpose: Colorectal cancer (CRC) incidence is increasing in adults younger than 50 years. This study evaluated clinicopathological characteristics and outcome of adolescent and young adult (AYA)-onset sporadic CRC patients. Methods: Medical records of patients who were diagnosed adenocarcinoma of colon or rectum at Siriraj Hospital between 2007 and 2018 were retrospectively reviewed. The patients were classified into two groups: AYA-onset CRC (age 15-39 years) and adult-onset CRC (age >50 years). Associations between sporadic microsatellite stable (MSS) AYA-/adult-onset CRC and clinicopathological features and outcome were evaluated. Results: A total of 203 patients were diagnosed with AYA-onset CRC with no known history of familial CRC syndromes, 119 had data on mismatch repair status; 98 confirmed MSS CRC. AYA-onset CRC patients were commonly found with left-sided rather than right-sided tumors (77.1% vs. 22%) and late stage of disease (80.7% in stage III-IV vs. 19.3% in stage I-II). Compared with adult-onset CRC (218 patients), AYA-onset MSS CRC had more patients with female gender (p = 0.038), perineural invasion (p = 0.003), and signet ring cell/mucinous histology (p = 0.132). On univariate analysis, male gender and mucinous/signet ring cell histology had worse overall survival (OS) (p = 0.004 and p = 0.072, respectively) and remained significant in multivariate analysis for signet ring cell histology (p = 0.008). There was no difference in disease-free survival and OS between both age groups. Conclusion: Sporadic MSS AYA-onset CRC patients were associated with female gender and aggressive pathological characteristics. However, there was no difference in survival outcome between AYA-onset and adult-onset groups.

Randomized, double-blind, placebo-controlled study of aprepitant versus two dosages of olanzapine with ondansetron plus dexamethasone for prevention of chemotherapy-induced nausea and vomiting in patients receiving high-emetogenic chemotherapy.

PURPOSE: We assessed the efficacy of aprepitant (APR) or 10 or 5 mg OLN (OLN10 or OLN5) plus ondansetron and dexamethasone for chemotherapy-induced nausea/vomiting (CINV) prophylaxis in patients receiving high-emetogenic chemotherapy (HEC). METHODS: Patients who received doxorubicin + cyclophosphamide or cisplatin were given intravenous ondansetron and dexamethasone prior to chemotherapy and oral dexamethasone on days 2-4 and randomized 1:1:1 to receive APR125 on day 1 and APR80 on days 2-3 or OLN10 or OLN5 on days 1-4. Matched placebo controls were used. The primary endpoint was no nausea in ≤ 120 h. Secondary endpoints included CINV severity, complete response (CR) rate, adverse effects (AE), and quality of life. RESULTS: Of 141 patients, 104 received AC and 37 received cisplatin. The no-nausea rates were 33% (APR), 43.2% (OLN10; p = 0.24), and 37% (OLN5; p = 0.87). Grades 2-4 nausea were experienced by fewer patients for OLN10 than for APR (24-120 h, 8.7% vs. 27.7%, respectively; p = 0.02; overall period, 19.6% vs. 40.4%, respectively; p = 0.03). The median visual analog scale nausea score from 24 to 120 h was significantly lower for OLN10 (2.3) than for APR (1.2, p = 0.03). The degrees of vomiting, CR, and AE were similar between the APR and OLN10 groups. CINV was similar between the OLN5 and APR groups. CONCLUSIONS: Nausea was less severe for OLN10 than for APR in patients receiving HEC, but other measures were similar. CINV prevention efficacy was comparable between OLN5 and APR.

Global differences in the prevalence of the CpG island methylator phenotype of colorectal cancer.

BACKGROUND: CpG Island Methylator Phenotype (CIMP) is an epigenetic phenotype in CRC characterized by hypermethylation of CpG islands in promoter regions of tumor suppressor genes, leading to their transcriptional silencing and loss of function. While the prevalence of CRC differs across geographical regions, no studies have compared prevalence of CIMP-High phenotype across regions. The purpose of this project was to compare the prevalence of CIMP across geographical regions after adjusting for variations in methodologies to measure CIMP in a meta-analysis. METHODS: We searched PubMed, Medline, and Embase for articles focusing on CIMP published from 2000 to 2018. Two reviewers independently identified 111 articles to be included in final meta-analysis. We classified methods used to quantify CIMP into 4 categories: a) Classical (MINT marker) Panel group b) Weisenberg-Ogino (W-O) group c) Human Methylation Arrays group and d) Miscellaneous group. We compared the prevalence of CIMP across geographical regions after correcting for methodological variations using meta-regression techniques. RESULTS: The pooled prevalence of CIMP-High across all studies was 22% (95% confidence interval:21-24%; I2 = 94.75%). Pooled prevalence of CIMP-H across Asia, Australia, Europe, North America and South America was 22, 21, 21, 27 and 25%, respectively. Meta-regression analysis identified no significant differences in the prevalence of CIMP-H across geographical regions after correction for methodological variations. In exploratory analysis, we observed variations in CIMP-H prevalence across countries. CONCLUSION: Although no differences were found for CIMP-H prevalence across countries, further studies are needed to compare the influence of demographic, lifestyle and environmental factors in relation to the prevalence of CIMP across geographical regions.

High Frequency of KRAS Codon 146 and FBXW7 Mutations in Thai Patients with Stage II-III Colon Cancer.

Background: KRAS, NRAS, and BRAF gene mutations are the most clinically relevant and frequently reported in colorectal cancer (CRC). Although data on these genes are frequently reported in several counties, data specific to these genes among Thai population are scarce. The aim of this study was to investigate and identify molecular alterations associated with colon cancer in Thai population, and to determine the impact of these genetic aberrations on clinical outcome. Methods: DNA from 108 archived formalin-fixed, paraffin-embedded (FFPE) tissue samples that histologically confirmed adenocarcinoma of stage II-III colon cancer between 2010 and 2012 at Siriraj Hospital (Bangkok, Thailand) were extracted. Gene mutational analysis was performed by next-generation sequencing (NGS) using an Oncomine Solid Tumor DNA kit (Thermo Fisher Scientific, Inc., Waltham, MA, USA). Results: A total of 22 somatic gene mutations were detected. The mutation frequency observed in KRAS, NRAS, BRAF, PIK3CA, and FBXW7 mutations was 47.2%, 1.9%, 1.9%, 12%, and 14.8%, respectively. KRAS mutation codon 12, 13, 59, 61, 117, and 146 mutations were identified in 29.6%, 8.3%, 1.8%, 0.9%, 0.0%, and 8.3%, respectively. KRAS Exon 4 had better DFS compared with Exon 2 and 3. Conclusions: This study is the first to comprehensively report hotspot mutations using NGS in Thai colon cancer patients. The most commonly identified gene mutation frequencies among Thai patients (KRAS, NRAS, BRAF, TP53, and PIK3CA) were similar to the gene mutation frequencies reported in Western population, except for subgroup of KRAS codon 146 and FBXW7 mutations that had a slightly higher frequency.

Signet ring cell colorectal cancer: genomic insights into a rare subpopulation of colorectal adenocarcinoma.

BACKGROUND: Signet ring cell carcinoma (SRCC) is a rare subtype of colorectal cancer (CRC). The aim of this study was to characterise the genomic alterations and outcomes of SRCC. METHODS: Medical records of metastatic CRC (mCRC) patients whose tumours were evaluated by NGS analysis were reviewed. SC-mCRC were classified into two groups: SRCC (>50% signet ring cells) and adenocarcinoma (AC) with SC component (≤50% signet ring cells). RESULTS: Six hundred and sixty-five mCRC patients were included. Of the 93 mCRC cases with SC features, 63 had slides for review. Of those 63 cases, 35 were confirmed SRCC, and 28 were AC with SC component. Compared with AC group, KRAS and PIK3CA mutations (mts) were found in only 11% (OR: 0.13) and 3% (OR: 0.15) of SRCC cases, respectively. In contrast to the 44% rate of APC mts in AC group, only 3% of SRCC patients had APC mts (OR = 0.04). CONCLUSIONS: SRCC has distinct molecular features, including low rates of KRAS, PIK3CA and APC mts. Further study to identify activation pathways and potential therapeutic targets are needed.

Dependency of Cholangiocarcinoma on Cyclin D-Dependent Kinase Activity.

Cholangiocarcinoma (CCA) is a bile duct cancer with a very poor prognosis. Currently, there is no effective pharmacological treatment available for it. We showed that CCA ubiquitously relies on cyclin-dependent kinases 4 and 6 (CDK4/6) activity to proliferate. Primary CCA tissues express high levels of cyclin D1 and the specific marker of CDK4/6 activity, phospho-RB Ser780. Treatment of a 15-CCA cell line collection by pharmacological CDK4/6 inhibitors leads to reduced numbers of cells in the S-phase and senescence in most of the CCA cell lines. We found that expression of retinoblastoma protein (pRB) is required for activity of the CDK4/6 inhibitor, and that loss of pRB conferred CDK4/6 inhibitor-drug resistance. We also identified that sensitivity of CCA to CDK4/6 inhibition is associated with the activated KRAS signature. Effectiveness of CDK4/6 inhibition for CCA was confirmed in the three-dimensional spheroid-, xenograft-, and patient-derived xenograft models. Last, we identified a list of genes whose expressions can be used to predict response to the CDK4/6 inhibitor. Conclusion: We investigated a ubiquitous dependency of CCA on CDK4/6 activity and the universal response to CDK4/6 inhibition. We propose that the CDK4/6-pRB pathway is a suitable therapeutic target for CCA treatment.

KRAS-IRF2 Axis Drives Immune Suppression and Immune Therapy Resistance in Colorectal Cancer.

The biological functions and mechanisms of oncogenic KRASG12D (KRAS∗) in resistance to immune checkpoint blockade (ICB) therapy are not fully understood. We demonstrate that KRAS∗ represses the expression of interferon regulatory factor 2 (IRF2), which in turn directly represses CXCL3 expression. KRAS∗-mediated repression of IRF2 results in high expression of CXCL3, which binds to CXCR2 on myeloid-derived suppressor cells and promotes their migration to the tumor microenvironment. Anti-PD-1 resistance of KRAS∗-expressing tumors can be overcome by enforced IRF2 expression or by inhibition of CXCR2. Colorectal cancer (CRC) showing higher IRF2 expression exhibited increased responsiveness to anti-PD-1 therapy. The KRAS∗-IRF2-CXCL3-CXCR2 axis provides a framework for patient selection and combination therapies to enhance the effectiveness of ICB therapy in CRC.