Transposon DNA sequences facilitate the tissue-specific gene transfer of circulating tumor DNA between human cells.

The exchange of genes between cells is known to play an important physiological and pathological role in many organisms. We show that circulating tumor DNA (ctDNA) facilitates cell-specific gene transfer between human cancer cells and explain part of the mechanisms behind this phenomenon. As ctDNA migrates into the nucleus, genetic information is transferred. Cell targeting and ctDNA integration require ERVL, SINE or LINE DNA sequences. Chemically manufactured AluSp and MER11C sequences replicated multiple myeloma (MM) ctDNA cell targeting and integration. Additionally, we found that ctDNA may alter the treatment response of MM and pancreatic cancer models. This study shows that retrotransposon DNA sequences promote cancer gene transfer. However, because cell-free DNA has been detected in physiological and other pathological conditions, our findings have a broader impact than just cancer. Furthermore, the discovery that transposon DNA sequences mediate tissue-specific targeting will open up a new avenue for the delivery of genes and therapies.

Deciphering cellular plasticity in pancreatic cancer for effective treatments.

Cellular plasticity and therapy resistance are critical features of pancreatic cancer, a highly aggressive and fatal disease. The pancreas, a vital organ that produces digestive enzymes and hormones, is often affected by two main types of cancer: the pre-dominant ductal adenocarcinoma and the less common neuroendocrine tumors. These cancers are difficult to treat due to their complex biology characterized by cellular plasticity leading to therapy resistance. Cellular plasticity refers to the capability of cancer cells to change and adapt to different microenvironments within the body which includes acinar-ductal metaplasia, epithelial to mesenchymal/epigenetic/metabolic plasticity, as well as stemness. This plasticity allows heterogeneity of cancer cells, metastasis, and evasion of host's immune system and develops resistance to radiation, chemotherapy, and targeted therapy. To overcome this resistance, extensive research is ongoing exploring the intrinsic and extrinsic factors through cellular reprogramming, chemosensitization, targeting metabolic, key survival pathways, etc. In this review, we discussed the mechanisms of cellular plasticity involving cellular adaptation and tumor microenvironment and provided a comprehensive understanding of its role in therapy resistance and ways to overcome it.

DNA-PK is activated by SIRT2 deacetylation to promote DNA double-strand break repair by non-homologous end joining.

DNA-dependent protein kinase (DNA-PK) plays a critical role in non-homologous end joining (NHEJ), the predominant pathway that repairs DNA double-strand breaks (DSB) in response to ionizing radiation (IR) to govern genome integrity. The interaction of the catalytic subunit of DNA-PK (DNA-PKcs) with the Ku70/Ku80 heterodimer on DSBs leads to DNA-PK activation; however, it is not known if upstream signaling events govern this activation. Here, we reveal a regulatory step governing DNA-PK activation by SIRT2 deacetylation, which facilitates DNA-PKcs localization to DSBs and interaction with Ku, thereby promoting DSB repair by NHEJ. SIRT2 deacetylase activity governs cellular resistance to DSB-inducing agents and promotes NHEJ. SIRT2 furthermore interacts with and deacetylates DNA-PKcs in response to IR. SIRT2 deacetylase activity facilitates DNA-PKcs interaction with Ku and localization to DSBs and promotes DNA-PK activation and phosphorylation of downstream NHEJ substrates. Moreover, targeting SIRT2 with AGK2, a SIRT2-specific inhibitor, augments the efficacy of IR in cancer cells and tumors. Our findings define a regulatory step for DNA-PK activation by SIRT2-mediated deacetylation, elucidating a critical upstream signaling event initiating the repair of DSBs by NHEJ. Furthermore, our data suggest that SIRT2 inhibition may be a promising rationale-driven therapeutic strategy for increasing the effectiveness of radiation therapy.

Understanding the molecular mechanisms that regulate pancreatic cancer stem cell formation, stemness and chemoresistance: A brief overview.

Pancreatic cancer is one of the most aggressive cancers worldwide due to the resistances to conventional therapies and early metastasis. Recent research has shown that cancer stem cell populations modulate invasiveness, recurrence, and drug resistance in various cancers, including pancreatic cancer. Pancreatic cancer stem cells (PaCSCs) are characterized by their high plasticity and self-renewal capacities that endow them with unique metabolic, metastatic, and chemoresistant properties. Understanding the exact molecular and signaling mechanisms that underlay malignant processes in PaCSCs is instrumental for developing novel therapeutic modalities that overcome the limitations of current therapeutic regimens. In this paper, we provide an updated review of the latest research in the field and summarize the current knowledge of PaCSCs characteristics, cellular metabolism, stemness, and drug resistance. We explore how the crosstalk between the TME and PaCSCs influences stemness. We also highlight some of the key signalling pathways involved in PaCSCs stemness and drug evasion. The aim of this review is to explore how PaCSCs develop, maintain their properties, and drive tumor relapse in PC. The last section explores some of the latest therapeutic strategies aimed at targeting PaCSCs.

Epigenetics in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and has a high fatality rate. Genetic and epigenetic aberrations are commonly observed in HCC. The epigenetic processes include chromatin remodelling, histone alterations, DNA methylation, and noncoding RNA (ncRNA) expression and are connected with the progression and metastasis of HCC. Due to their potential reversibility, these epigenetic alterations are widely targeted for the development of biomarkers. In-depth understanding of the epigenetics of HCC is critical for developing rational clinical strategies that can provide a meaningful improvement in overall survival and prediction of therapeutic outcomes. In this article, we have summarised the epigenetic modifications involved in HCC progression and highlighted the potential biomarkers for diagnosis and drug development.

Aberrant transcription factors in the cancers of the pancreas.

Transcription factors (TFs) are essential for proper activation of gene during the process of organogenesis, differentiation, lineage specificity. Reactivation or dysregulation of TFs regulatory networks could lead to deformation of organs, diseases including various malignancies. Currently, understanding the mechanism of oncogenesis became a necessity for the development of targeted therapeutic strategy for different cancer types. It is evident that many TFs go awry in cancers of the pancreas such as pancreatic ductal adenocarcinoma (PDAC) and pancreatic neuroendocrine neoplasms (PanNENs). These mutated or dysregulated TFs abnormally controls various signaling pathways in PDAC and PanNENs including RTK, PI3K-PTEN-AKT-mTOR, JNK, TGF-ß/SMAD, WNT/ß-catenin, SHH, NOTCH and VEGF which in turn regulate different hallmarks of cancer. Aberrant regulation of such pathways have been linked to the initiation, progression, metastasis, and resistance in pancreatic cancer. As of today, a number of TFs has been identified as crucial regulators of pancreatic cancer and a handful of them shown to have potential as therapeutic targets in pre-clinical and clinical settings. In this review, we have summarized the current knowledge on the role and therapeutic usefulness of TFs in PDAC and PanNENs.

Connecting the Human Microbiome and Pancreatic Cancer.

Pancreatic cancer is a deadly disease that is increasing in incidence throughout the world. There are no clear causal factors associated with the incidence of pancreatic cancer; however, some correlation to smoking, diabetes and alcohol has been described. Recently, a few studies have linked the human microbiome (oral and gastrointestinal tract) to pancreatic cancer development. A perturbed microbiome has been shown to alter normal cells while promoting cancer-related processes such as increased cell signaling, immune system evasion and invasion. In this article, we will review in detail the alterations within the gut and oral microbiome that have been linked to pancreatic cancer and explore the ability of other microbiomes, such as the lung and skin microbiome, to contribute to disease development. Understanding ways to identify a perturbed microbiome can result in advancements in pancreatic cancer research and allow for prevention, earlier detection and alternative treatment strategies for patients.

Targeting KRAS in pancreatic cancer: new drugs on the horizon.

Kirsten Rat Sarcoma (KRAS) is a master oncogene involved in cellular proliferation and survival and is the most commonly mutated oncogene in all cancers. Activating KRAS mutations are present in over 90% of pancreatic ductal adenocarcinoma (PDAC) cases and are implicated in tumor initiation and progression. Although KRAS is a critical oncogene, and therefore an important therapeutic target, its therapeutic inhibition has been very challenging, and only recently specific mutant KRAS inhibitors have been discovered. In this review, we discuss the activation of KRAS signaling and the role of mutant KRAS in PDAC development. KRAS has long been considered undruggable, and many drug discovery efforts which focused on indirect targeting have been unsuccessful. We discuss the various efforts for therapeutic targeting of KRAS. Further, we explore the reasons behind these obstacles, novel successful approaches to target mutant KRAS including G12C mutation as well as the mechanisms of resistance.

Survival Outcomes of Adjuvant Chemotherapy in Elderly Patients with Stage III Colon Cancer.

BACKGROUND: The survival impact of multi-agent (MAC) compared with single-agent (SAC) adjuvant chemotherapy (AC) in elderly patients with stage III colon cancer (CC) remains controversial. The aim of this study was to compare survival outcomes of MAC and SAC in this population utilizing the National Cancer Database (NCDB). PATIENTS AND METHODS: Patients aged ≥70 years with pathological stage III CC diagnosed in 2004-2015 were identified in the NCDB. Univariate and multivariable analyses were conducted, and Kaplan-Meier analysis and Cox proportional hazard models were used to identify associations between MAC vs. SAC and overall survival (OS). RESULTS: Among 41 707 elderly patients (≥70 years old) with stage III CC, about half (n = 20 257; 48.5%) received AC; the majority (n = 12 923, 63.8%) received MAC. The median age was 79 (range 70-90). The majority were female (n = 11 201, 55.3%), Caucasians (88%) and had moderately differentiated tumor grade (n = 12 619, 62.3%), tumor size >4 cm (11 785, 58.2%), and negative surgical margins (18 496, 91.3%). Low-risk stage III CC constituted 50.6% (n = 10 264) of the study population. High-risk stage III CC was associated with worse OS compared with low-risk disease (HR 0.35, 0.34-0.36, P < .001). Multi-agent chemotherapy was associated with a better 5-year OS compared with SAC (P < .001). High-risk stage III patients who received MAC vs. SAC had an OS of 4.2 vs. 3.4 years, respectively (P < .001). Low-risk stage III patients who received MAC vs. SAC had a median OS of 8.5 vs. 7 years (P < .001). In univariate and multivariable analyses, male sex, positive surgical margin, insurance and facility types, age, year of diagnosis, tumor size, and Charlson-Deyo score of >2 were associated with worse OS (P < .05). CONCLUSIONS: Any adjuvant chemotherapy has a trend of survival benefits. Multi-agent chemotherapy seems to have an enhanced benefit in the 70-75 age group. Multi-agent chemotherapy seemed to have similar efficacy as SAC in those aged >76 years.

Comparing Somatostatin Analogs in the Treatment of Advanced Gastroenteropancreatic Neuroendocrine Tumors.

BACKGROUND: The 2 approved somatostatin analogs (SSAs) in the first-line treatment of advanced, well-differentiated gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are octreotide long-acting release (Sandostatin LAR) and somatuline depot (Lanreotide). The study's objective was to compare progression-free survival (PFS) and overall survival (OS) of patients (pts) with GEP-NETs treated with somatuline or octreotide LAR. Pts and Methods: Pts with advanced well-differentiated GEP-NET who received either SSA at Emory University between 1995 and 2019 were included after institutional review board approval. The primary end point was PFS, defined as time to disease progression (according to the Response Evaluation Criteria in Solid Tumors, version 1.1, or clinical progression) or death. The secondary end point was OS. Kaplan-Meier curves were generated, and log-rank tests were conducted to compare the survival outcomes. RESULTS: A total of 105 pts were identified. The mean age was 62.1 years (SD ± 11.8). The male-to-female ratio was 51:54. The majority (N = 69, 65.7%) were white. Most pts had grade 2 (G2) disease (N = 44, 41.9%). Primary location was small bowel in 58 (55.2%), pancreas in 27 (25.7%), and other in 20 (19.0%). Functional tumors were defined in 32 pts distributed equally between the 2 groups. Distribution of treatment was similar in the 2 groups, with 54 receiving octreotide LAR and 51 receiving somatuline depot. The median PFS for the octreotide LAR and somatuline depot groups was 12 months (95% CI, 6-18 months) and 10.8 months (95% CI, 6-15.6 months), respectively, and the difference was not statistically significant (p = 0.2665). For pts with G1 disease, the median PFS for the octreotide LAR and somatuline depot was 8.4 versus 32.4 months, respectively, and the difference was not statistically significant (p = 0.159). For G2 disease, the difference in median PFS between octreotide LAR and somutaline depot groups was statistically significant (12 vs. 7.2 months, respectively; p = 0.0372). The mean follow-up time for octreotide LAR was 21.6 months versus 11.3 months for somatuline depot. CONCLUSIONS: Overall, there was no difference in PFS between octreotide LAR and somatuline depot for pts with well-differentiated, metastatic GEP-NETs. A prospective study is worth designing selecting for G.

Targeting T regulatory cells: Their role in colorectal carcinoma progression and current clinical trials.

Colorectal cancer (CRC) is classified as the third leading cancer globally and one of the major causes of morbidity and mortality around the world. The interaction of the immune system with the cancer cells plays a vital role in CRC progression. Regulatory T cells (Tregs) are a form of T cells, which regulate and suppress unwanted activation of the immune system and play a major role in preventing autoimmune diseases. Tregs exhibit a significant role in immune modulation during CRC progression through accumulation in the tumor microenvironment (TME) and suppression of immunity against tumor specific antigens promoting tumor progression. The role of Tregs in CRC progression and its interaction with other immune cells within CRC TME and current clinical trials were reviewed in this paper.

Correlates of financial toxicity in adult cancer patients and their informal caregivers.

BACKGROUND: Financial toxicity is commonly reported by cancer patients, but few studies have assessed caregiver perceptions. We aimed to validate the modified Comprehensive Score for Financial Toxicity (COST) in cancer caregivers, identify factors associated with financial toxicity in both patients and caregivers, and assess the association of caregiver financial toxicity with patient and caregiver outcomes. METHODS: Using a convenience sampling method, 100 dyads of adult cancer patients and a primary caregiver visiting outpatient oncology clinics (Jan-Sep 2019) were recruited. We assessed the internal consistency and convergent and divergent validity of the modified COST. Multivariable analyses identified correlates of financial toxicity. Association of financial toxicity with care non-adherence, lifestyle-altering behaviors (e.g., home refinance/sale, retirement/saving account withdrawal), and quality of life (QOL) was investigated. RESULTS: Recruited patient vs. caregiver characteristics were as follows: mean age: 60.6 vs. 56.5; 34% vs. 46.4% female; 79% vs. 81.4% white. The caregiver COST measure demonstrated high internal consistency (Cronbach α = 0.91). In patients, older age (B, 0.3 [95% CI, 0.1-0.4]) and higher annual household income (B, 14.3 [95% CI, 9.3-19.4]) correlated with lower financial toxicity (P < 0.05). In caregivers, lower patient financial toxicity (B, 0.4 [95% CI, 0.2-0.6]) and cancer stages 1-3 (compared to stage 4) (B, 4.6 [95% CI, 0.4-8.8]) correlated with lower financial toxicity (P < 0.05). Increased caregiver financial toxicity correlated with higher care non-adherence in patients, increased lifestyle-altering behaviors, and lower QOL in patients and caregivers (P < 0.05). CONCLUSION: The COST measure can also be used to assess caregiver financial toxicity. Caregivers' financial toxicity was associated with negative outcomes for both dyad members.

CheckMate 040 cohort 5: A phase I/II study of nivolumab in patients with advanced hepatocellular carcinoma and Child-Pugh B cirrhosis.

BACKGROUND & AIMS: Patients with advanced hepatocellular carcinoma (aHCC) and Child-Pugh B liver function are often excluded from clinical trials. In previous studies, overall survival for these patients treated with sorafenib was ∼3-5 months; thus, new treatments are needed. Nivolumab, alone or in combination with ipilimumab, is conditionally approved in the United States to treat patients with aHCC who previously received sorafenib. We describe nivolumab monotherapy outcomes in patients with Child-Pugh B status. METHODS: This phase I/II, open-label, non-comparative, multicentre trial (27 centres) included patients with Child-Pugh B (B7-B8) aHCC. Patients received intravenous nivolumab 240 mg every 2 weeks until unacceptable toxicity or disease progression. Primary endpoints were objective response rate (ORR) by investigator assessment (using Response Evaluation Criteria in Solid Tumors v1.1) and duration of response. Safety was assessed using National Cancer Institute Common Terminology Criteria for Adverse Events v4.0. RESULTS: Twenty-five sorafenib-naive and 24 sorafenib-treated patients began treatment between November 2016 and October 2017 (median follow-up, 16.3 months). Investigator-assessed ORR was 12% (95% CI 5-25%) with 6 patients responding; disease control rate was 55% (95% CI 40-69%). Median time to response was 2.7 months (interquartile range, 1.4-4.2), and median duration of response was 9.9 months (95% CI 9.7-9.9). Treatment-related adverse events (TRAEs) were reported in 25 patients (51%) and led to discontinuation in 2 patients (4%). The most frequent grade 3/4 TRAEs were hypertransaminasemia (n = 2), amylase increase (n = 2), and aspartate aminotransferase increase (n = 2). The safety of nivolumab was comparable to that in patients with Child-Pugh A aHCC. CONCLUSIONS: Nivolumab showed clinical activity and favourable safety with manageable toxicities, suggesting it could be suitable for patients with Child-Pugh B aHCC. LAY SUMMARY: In patients with advanced hepatocellular carcinoma, almost all systemic therapies require very good liver function, i.e. Child-Pugh A status. The evidence from this study suggests that nivolumab shows clinical activity and an acceptable safety profile in patients with hepatocellular carcinoma with Child-Pugh B status who have mild to moderate impairment of liver function or liver decompensation that might rule out other therapies. Further studies are warranted to assess the safety and efficacy of nivolumab in this patient population. CLINICAL TRIAL NUMBER: NCT01658878.

Mismatch Repair (MMR) Gene Alteration and BRAF V600E Mutation Are Potential Predictive Biomarkers of Immune Checkpoint Inhibitors in MMR-Deficient Colorectal Cancer.

BACKGROUND: Immune checkpoint inhibitor (ICI) therapy is highly effective in metastatic mismatch repair-deficient (MMR-D) colorectal cancer (CRC). In this study, we evaluated molecular and clinical predictors of ICI response in MMR-D CRC. MATERIALS AND METHODS: Patient databases at four cancer institutions were queried. The Fisher exact test was performed to test the association of clinical and molecular markers. The Kaplan-Meier method was used to estimate progression-free survival (PFS) and compared by the log-rank test. Twelve- and 24-month PFS rates were compared by the Z test. RESULTS: A total of 60 patients with CRC with MMR-D/microsatellite instability-high who previously received ICIs were identified. Patients with liver metastasis had a lower overall response rate as compared with other sites of metastasis (36.4% vs. 68.7%; p = .081). Patients with MLH1/PMS2 loss had worse 1-year and 2-year PFS rates compared with patients with MSH2/MSH6 loss (84.2% vs. 57.8% and 78.2% vs. 54.2%, respectively; p < .001). There were improved 1-year and 2-year PFS rates in patients with wild-type BRAF when compared with patients with BRAF V600E mutation (73.3% vs. 40%, and 73.3% vs. 26.7%; respectively; p < .001). Patients aged >65 had significantly worse PFS rates as compared with patients aged ≤65 (p < .001). CONCLUSION: BRAF V600E mutation, MLH1 and/or PMS2 loss, as well as age >65 years and liver metastasis, may be predictive of duration of ICI response in patients with MMR-D CRC. Larger cohorts are needed to confirm our findings. IMPLICATIONS FOR PRACTICE: The results of this study reveal clinically important biomarkers that potentially predict immune checkpoint inhibitor response in patients with mismatch repair-deficient colorectal cancer.

A multi-center, single-arm, phase Ib study of pembrolizumab (MK-3475) in combination with chemotherapy for patients with advanced colorectal cancer: HCRN GI14-186.

Modified FOLFOX6 is an established therapy for patients with metastatic colorectal cancer (mCRC). We conducted a single-arm phase Ib study to address the hypothesis that addition of pembrolizumab to this regimen could safely and effectively improve patient outcomes (NCT02375672). The relationship between immune biomarkers and clinical response were assessed in an exploratory manner. Patients with mCRC received concurrent pembrolizumab and modified FOLFOX6. The study included safety run-in for the first six patients. The primary objective was median progression-free survival (mPFS), with secondary objectives including median overall survival, safety, and exploratory assessment of immune changes. To assess immunological impact, peripheral blood was collected at baseline and during treatment. The levels of soluble factors were measured via bioplex, while a panel of checkpoint molecules and phenotypically defined cell populations were assessed with flow cytometry and correlated with RECIST and mPFS. Due to incidences of grade 3 and grade 4 neutropenia in the safety lead-in, the dose of mFOLFOX6 was reduced in the expansion cohort. Median PFS was 8.8 months and median OS was not reached at data cutoff. Best responses of stable disease, partial response, and complete response were observed in 43.3%, 50.0%, and 6.7% of patients, respectively. Several soluble and cellular immune biomarkers were associated with improved RECIST and mPFS. Immunosuppressive myeloid and T cell subsets that were analyzed were not associated with response. Primary endpoint was not superior to historic control. Biomarkers that were associated with improved response may be informative for future regimens combining chemotherapy with immune checkpoint inhibitors.

Should Signet Ring Cell Histology Alter the Treatment Approach for Clinical Stage I Gastric Cancer?

BACKGROUND: Surgery alone is standard-of-care for stage I gastric adenocarcinoma; however, clinicians can offer preoperative therapy for clinical stage I disease with signet ring cell histology, given its presumed aggressive biology. We aimed to assess the validity of this practice. METHODS: The National Cancer Database (2004-2015) was reviewed for patients with clinical stage I signet ring cell gastric adenocarcinoma who underwent treatment with surgery alone, perioperative chemotherapy, neoadjuvant therapy, or adjuvant therapy. Analysis was stratified by preoperative clinical/pathologic stage. Primary outcome was overall survival (OS). RESULTS: Of 1018 patients, median age was 60 years (±14); 53% received surgery alone (n = 542), 5% received perioperative chemotherapy (n = 47), 12% received neoadjuvant therapy (n = 125), and 30% received adjuvant therapy (n = 304). For clinical stage I disease, surgery alone was associated with an improved 5-year OS rate (71%) versus perioperative chemotherapy (58%), neoadjuvant therapy (38%), or adjuvant therapy (52%) [overall p < 0.01]. For pathologic stage I, surgery alone had equivalent or improved survival compared with perioperative, neoadjuvant, and adjuvant therapy (5-year OS: 78% vs. 89% [p = 0.77] vs. 64% [p = 0.04] vs. 84% [p = 0.99]). Adjuvant therapy was associated with improved 5-year OS compared with pretreatment for those patients upstaged (37%) to pathologic stage II/III (55% vs. 36% and 34% vs. 7%; all p < 0.01). CONCLUSIONS: This stage-specific study demonstrates improved survival with surgery alone for clinical stage I signet ring cell gastric adenocarcinoma. Despite 37% of clinical stage I patients being upstaged to pathologic stage II/III, adjuvant therapy offers a favorable rescue strategy, with improved outcomes compared with those treated preoperatively. Surgery alone also affords similar or improved survival for pathologic stage I disease versus multimodality therapy. This study challenges the bias to overtreat stage I signet ring cell gastric adenocarcinoma.

Perioperative therapy in metastatic colorectal cancer: Pattern of use and survival outcomes.

BACKGROUND: Multimodality therapy of metastatic colorectal cancer (mCRC) is currently considered the standard of care. The aim of this study was to evaluate the impact of perioperative therapy on surgical resection in mCRC. METHODS: The National Cancer Database was analyzed for affected patients between 2004 and 2013. Univariate and multivariate analyses were done to identify factors associated with patient outcomes. Kaplan-Meier analysis and Cox proportional hazards models were used for the association between patient characteristics and survival. RESULTS: About 61,940 patients with mCRC were identified. Mean age = 63.4 years (SD ± 14). About 69% had a colon primary and 32% had only one metastatic site. Only 49% of those who underwent surgery for both primary and metastatic sites received postoperative chemotherapy (p < .001). Negative prognostic factors included no chemotherapy received (hazard ratio [HR], 2.32; 2.27-2.37; p < .001), more than three metastatic sites (HR, 2.28; 2.09-2.48; p < .001), year of diagnosis between 2004 and 2008 (HR, 1.71; 1.15-1.20; p < .001) and colon tumor location with right worse than left-sided (HR, 1.21; 1.19-1.24; p < .001). Five-year overall survival for resection of the primary and metastatic site (28.2%) was higher than for no surgical treatment (4.7%). CONCLUSION: Perioperative therapy was associated with improved survival, following resection of metastatic sites or primary tumor.

Napabucasin (BBI 608), a potent chemoradiosensitizer in rectal cancer.

BACKGROUND: The induction of reactive oxygen species (ROS) represents a viable strategy for enhancing the activity of radiotherapy. The authors hypothesized that napabucasin would increase ROS via its ability to inhibit NAD(P)H:quinone oxidoreductase 1 and potentiate the response to chemoradiotherapy in rectal cancer via distinct mechanisms. METHOD: Proliferation studies, colony formation assays, and ROS levels were measured in HCT116 and HT29 cell lines treated with napabucasin, chemoradiation, or their combination. DNA damage (pγH2AX), activation of STAT, and downstream angiogenesis were evaluated in both untreated and treated cell lines. Finally, the effects of napabucasin, chemoradiotherapy, and their combination were assessed in vivo with subcutaneous mouse xenograft models. RESULTS: Napabucasin significantly potentiated the growth inhibition of chemoradiation in both cell lines. Napabucasin increased ROS generation. Inhibition of ROS by N-acetylcysteine decreased the growth inhibitory effect of napabucasin alone and in combination with chemoradiotherapy. Napabucasin significantly increased pγH2AX in comparison with chemoradiotherapy alone. Napabucasin reduced the levels of pSTAT3 and VEGF and inhibited angiogenesis through an ROS-mediated effect. Napabucasin significantly potentiated the inhibition of growth and blood vessel formation by chemoradiotherapy in mouse xenografts. CONCLUSION: Napabucasin is a radiosensitizer with a novel mechanism of action: increasing ROS production and inhibiting angiogenesis. Clinical trials testing the addition of napabucasin to chemoradiotherapy in rectal cancer are needed.

Survival outcome of adjuvant chemotherapy in deficient mismatch repair stage III colon cancer.

BACKGROUND: The prognostic impact of DNA mismatch repair (MMR) status remains controversial in patients with stage III colon cancer who are treated with adjuvant chemotherapy (AC). The aim of this study was to evaluate the survival outcome of AC in deficient mismatch repair (dMMR)/microsatellite instable (MSI) stage III CC. METHODS: Patients with pathological stage III CC between 2010 and 2013 were identified from the National Cancer Database using International Classification of Diseases for Oncology (3rd Edition) morphology and topography codes 8140, 8480, and C18.0-18.8. Patients with pathologic stage T3N2, T4N1, or T4N were considered high risk; patients with stage T3N1 were considered low risk. Univariate and multivariable analyses were conducted, and Kaplan-Meier analysis and Cox proportional hazards models were used to identify the association between AC and overall survival (OS). RESULTS: A total of 9226 patients with pathological stage III CC were identified, of which 2384 (25.8%) were MSI-high (MSI-H) and met the inclusion criteria of the final analysis. MSI-low (MSI-L) patients (n = 6842) were excluded. There was a preponderance of women (55.0% [n = 1311]), and 76.6% (n = 1825) of patients were non-Hispanic white. The median age was 65 years (range, 19-90 years). The primary sites were the cecum (29.7% [n = 707]), ascending colon (26.0% [n = 620]), sigmoid colon (17.2% [n = 410]), and transverse colon (10.8% [n = 257]). The most common tumor grade was moderately differentiated (n = 50.4% [1202]), followed by poorly differentiated (34.1% [n = 813]) and well differentiated (5.1% [n = 121]). High-risk pathologic stage III CC (T4N1, TxN2) constituted 51.0% (n = 1215) of the study population. High-risk stage III was associated with worse OS compared with low-risk stage III on univariate (P < .001) analysis and displayed a similar trend on multivariable analysis, without a statistically significant difference. Multiagent AC was associated with improved OS compared with no treatment on univariate (P < .001) and multivariable (P < .001) analysis. When stratified by risk status, multiagent AC was associated with improved OS compared with no treatment for high-risk (P < .001) and low-risk (P < .001) stage III disease. CONCLUSION: Adjuvant chemotherapy is associated with better OS in stage III dMMR/MSI-H CC. An enhanced benefit was shown for high-risk stage III disease.

Frequency and clinicopathologic associations of DNA mismatch repair protein deficiency in ampullary carcinoma: Routine testing is indicated.

BACKGROUND: The significance of DNA mismatch repair (MMR) deficiency in ampullary cancers (ACs) has not been established. METHODS: In total, 127 ACs with invasive carcinomas measuring ≥3 mmthat had adequate tissue were analyzed immunohistochemically. RESULTS: MMR loss was detected in 18% of ACs (higher than in colorectal cancers). Twelve tumors with MLH1-PMS2 loss were negative for BRAF V600E mutation, suggesting a Lynch syndrome association. MMR-deficient tumors (n = 23), comparedwith MMR-intact tumors (n = 104), showed a striking male predominance (male:female ratio, 4.7). Although the deficient tumors had slightly larger invasion size (2.7 vs 2.1 cm), they also had more expansile growth and less invasiveness, including less perineural invasion, and they ultimately had lower tumor (T) classification and less lymph node metastasis (30% vs 53%; P = .04). More important, patients who had MMR-deficient tumors had better clinical outcomes, with a 5-year overall survival rate of 68% versus 45% (P = .03), which was even more pronounced in those who had higher Tclassification (5-year overall survival, 69% vs 34%; P = .04). MMR deficiencyhad a statistically significant association with medullary phenotype, pushing-border invasion, and tumor-infiltrating immune cells, and it occurred more frequently in ampullary-duodenal type tumors. Programed cell death-ligand 1 (PD-L1) levels analyzed in the 22 MMR-deficient ACs revealed that all medullary carcinomas were positive. Nonmedullary MMR-deficient carcinomas expressed PD-L1 in 33% of tumors cells according to the criteria for a combined positive score ≥1, but all were negative according to the tumor proportion score≥1 method. CONCLUSIONS: In ACs, MMR deficiency is even more frequent (18%) than in colon cancer and often has a Lynch-suggestive profile, thus routine testing is warranted. Male gender, pushing-border infiltration, ampullary-duodenal origin, medullary histology, and tumor-related inflammation have a significantly higher association with MMR deficiency. MMR-deficient tumors have less aggressive behavior. PD-L1 expression is common in medullary-phenotype ACs, thus immunotherapy should be considered at least for this group.