Extracellular water to total body water ratio, a novel predictor of recurrence in patients with colorectal cancer

Background

Total body water (TBW) fraction, which accounts for 60% of body weight, is an important indicator of body composition, and the extracellular water to TBW ratio (ECW/TBW) is reportedly useful in predicting clinical outcomes of patients with organ disorders. We aimed to clarify the clinical impact of preoperative ECW/TBW status on survival outcomes in cancer patients.

Methods

We used a database of 320 colorectal cancer (CRC) patients who underwent potentially curative resections. Preoperative ECW/TBW was measured using a bioelectrical impedance analysis (BIA), and its correlation with patient survival outcomes, clinicopathological factors, laboratory data, and comorbidities were analyzed.

Results

A high preoperative ECW/TBW was significantly associated with poorer relapse-free survival (RFS; p = 0.001) and overall survival (OS; p = 0.003). A high ECW/TBW ratio was significantly associated with older age (p < 0.001), low BMI (p = 0.009), and right-sided tumors (p = 0.03). In a multivariate analysis, a high ECW/TBW significantly predicted a higher RFS mortality (HR: 2.07, 95% CI: 1.10-3.88, p = 0.024) and OS mortality (HR: 3.23, 95% CI: 1.25-8.36, p = 0.016). Furthermore, a high ECW/TBW was significantly associated with lower hemoglobin (p < 0.001) and albumin levels (p < 0.001), but not comorbidities.

Conclusions

A high preoperative ECW/TBW was a predictive factor for recurrence and poorer overall survival independent of the tumor, node, and metastasis (TNM) stage. Our data suggest that preoperative evaluation of ECW/TBW using BIA might serve as a novel tool for developing CRC treatment strategies.

The colon inflammatory index score can predict the survival outcome after resection of colorectal cancer: a retrospective multicentre study

PURPOSE

Many systemic inflammatory markers have been identified to be prognostic factors in various diseases, including colorectal cancer (CRC). The Colon Inflammatory Index (CII), which is based on the lactate dehydrogenase (LDH) level and the neutrophil-to-lymphocyte ratio (NLR), is reportedly a predictor of the outcome of chemotherapy in patients with metastatic CRC. This retrospective review study aimed to determine whether CII can predict the prognosis after surgical resection of CRC.

METHODS

A total of 1,273 patients who underwent CRC resection were enrolled and divided into a training cohort (n = 799) and a validation cohort (n = 474). The impact of the preoperative CII score on overall survival (OS) and recurrence-free survival (RFS) was assessed.

RESULTS

In the training cohort, the CII score was good in 569 patients (71.2%), intermediate in 209 (26.2%), and poor in 21 (2.6%). There were significant between-group differences in body mass index, American Society of Anaesthesiologists physical status, and preoperative tumour markers. The 5-year OS rate was significantly lower in patients with an intermediate or poor CII score (CII risk) than in those with no CII risk (73.8% vs. 84.2%; p < 0.001, log-rank test). In multivariate analysis, CII risk remained a significant independent predictor of poor OS (hazard ratio 1.75; 95% confidence interval 1.18-2.60; p = 0.006). In the validation cohort, the 5-year OS rate was significantly lower in patients with CII risk than in those with no CII risk (82.8% vs. 88.4%; p = 0.046, log-rank test).

CONCLUSION

These findings indicate that the CII can predict OS after resection of CRC.

Emerging evidence of immunotherapy for colorectal cancer

Since the advent of immune checkpoint inhibitors, which modulate the interplay between the tumor cell and immune system, immunotherapy has become widely recognized as a new standard treatment for cancers including microsatellite instability-high (MSI-H) colorectal cancer. Immune checkpoint inhibitors such as pembrolizumab and nivolumab (anti-PD-1 antibodies) that act in the effector phase of T cells and ipilimumab (anti-CTLA-4 antibody) that acts mainly in the priming phase are now in clinical use. These antibodies have shown therapeutic efficacy in MSI colorectal cancer patients who have failed to respond to existing standard therapies. Pembrolizumab is also strongly recommended as first-line therapy for MSI-H metastatic colorectal cancer. Therefore, the MSI status and tumor mutation burden of the tumor should be clarified before starting treatment. Because many patients do not respond to immune checkpoint inhibitors, combination therapies with immune checkpoint inhibitors, including chemotherapy, radiotherapy, or molecularly targeted agents, are being investigated. Furthermore, treatment methods for preoperative adjuvant therapy for rectal cancer are being developed.

Laparoscopic Observation of Adhesive Rectal Fixation after Gant-Miwa-Thiersch Procedure for Rectal Prolapse: A Case Report

In our previous report, we have noted an increase of computed tomography (CT) attenuation values in perirectal fat tissue after Gant-Miwa-Thiersch (GMT) procedure for rectal prolapse. Based on these results, we hypothesized that the GMT procedure may have a rectal fixation effect due to inflammatory adhesions extending to the mesorectum. Herein, we report a case of laparoscopic observation of perirectal inflammation after GMT. A 79-year-old woman with a history of seizures, stroke, subarachnoid hemorrhage, and spondylosis underwent the GMT procedure under general anesthesia in the lithotomy position for rectal prolapse measuring 10 cm in length. But rectal prolapse recurred 3 weeks after surgery. Therefore, an additional Thiersch procedure was performed. However, rectal prolapse still recurred, and laparoscopic suture rectopexy was performed 17 weeks after initial surgery. During rectal mobilization, marked edema and rough membranous adhesions were observed in the retrorectal space. The average CT attenuation value obtained 13 weeks after initial surgery was found to be significantly elevated in the mesorectum compared with the subcutaneous fat, especially in the posterior side (P < 0.05). These findings suggest that the extension of inflammation to the rectal mesentery after the GMT procedure may have strengthened adhesions in the retrorectal space.

Molecular profiling of signet-ring-cell carcinoma (SRCC) from the stomach and colon reveals potential new therapeutic targets

Signet ring cell carcinoma (SRCC) is rare: about 10% of gastric cancer (GC) and 1% of colorectal cancer (CRC). SRCC is associated with poor prognosis, however the underlying molecular characteristics are unknown. SRCCs were analyzed using NGS, immunohistochemistry, and in situ hybridization. Tumor mutational burden (TMB) was calculated based on somatic nonsynonymous missense mutations, and microsatellite instability (MSI) was evaluated by NGS of known MSI loci. A total of 8500 CRC and 1100 GC were screened. Seventy-six SRCC were identified from the CRC cohort (<1%) and 98 from the GC cohort (9%). The most frequently mutated genes in CRC-SRCC were TP53 (47%), ARID1A (26%), APC (25%); in GC-SRCC were TP53 (42%), ARID1A (27%), CDH1 (11%). When compared to non-SRCC histology (N = 3522), CRC-SRCC (N = 37) more frequently had mutations in BRCA1 (11% vs 1%, P < 0.001) and less frequently mutations in APC (19% vs 78%, P < 0.001), KRAS (22% vs 51%, P = 0.001) and TP53 (47% vs 73%, P = 0.001). Among the GC cohort, SRCC (N = 54) had a higher frequency of mutations in CDH1, BAP1, and ERBB2, compared to non-SRCC (N = 540). Our data suggest that SRCCs harbor a similar molecular profile, regardless of the tumor location. Tailored therapy may become available for these patients.

Activin A promotes cell proliferation, invasion and migration and predicts poor prognosis in patients with colorectal cancer

Activin A is a member of the transforming growth factor‑β superfamily of cytokines and displays various pathophysiological activities, including regulation of muscle catabolism and atrophy. Activin A expression is upregulated in several human cancer types and in certain pathologies, its expression is associated with poor prognosis. In the present study, activin A expression was assessed in colorectal cancer (CRC) tissue specimens from 157 patients with primary CRC and the relationship between activin A levels and clinicopathological characteristics, including skeletal muscle mass, and prognosis, was determined. Furthermore, the effects of knockdown of endogenous or exposure to exogenous activin A on the malignant behavior of human CRC cell lines were investigated in vitro. The results indicated that activin A mRNA was significantly upregulated in CRC tumor tissues compared with normal intestinal epithelium. High activin A expression was significantly associated with shorter cancer‑specific survival (P=0.047) and overall survival (P=0.014). According to a multivariate analysis, tumor activin A levels were an independent prognostic factor for overall survival (P=0.001). However, activin A mRNA levels were not associated with the skeletal muscle index. The in vitro experiments demonstrated that exposure to exogenous activin A increased the proliferation, invasion and migration of CRC cell lines, whereas knockdown of endogenous activin A had the opposite effects. In conclusion, activin A is an autocrine and paracrine regulator of CRC cell proliferation and high tumor expression of activin A is associated with poor prognosis in patients with CRC.

What are the factors predictive of postoperative complications in patients with colorectal cancer undergoing stenting as a bridge to surgery?

OBJECTIVE

Using a self-expanding metal stent as a bridge to surgery (BTS) is considered a reasonable strategy for patients with acute malignant large bowel obstruction. Since postoperative complications have a negative impact on patient survival, we aim to clarify the predictors of complications in patients undergoing BTS using a self-expanding metal stent.

METHODS

We conducted a retrospective review of 61 patients with colorectal cancer (CRC) who underwent stenting as a BTS at our institution. We analyzed the association of postoperative complications with clinicopathologic, surgical, and patient factors, and with the prestenting or preoperative laboratory data.

RESULTS

Both postoperative complications in general and severe complications were significantly associated with a longer stenotic-section length (p = 0.007 and p = 0.003), lower preoperative hemoglobin levels (p < 0.001 and p = 0.081), and lower prestenting hemoglobin levels (p = 0.006 and p = 0.042). Multivariate logistic regression analysis showed that lower prestenting (<13.0 g/dl) and preoperative (<11.5 g/dl) hemoglobin levels were independent predictive factors for postoperative complications (odds ratio [OR]: 4.15; 95% confidence interval [CI]: 1.07-18.90; p = 0.040; and OR: 4.93; 95% CI: 1.35-20.28; p = 0.016). A stenotic-section length of 5.0 cm or greater was predictive of severe complications (OR: 25.67; 95% CI: 1.95-1185.00; p = 0.011).

CONCLUSIONS

Our data suggest that lower hemoglobin levels before stenting and a longer length of the stenotic section of bowel might predict postoperative complications in patients with CRC undergoing BTS for obstruction.

The advanced lung cancer inflammation index is a novel independent prognosticator in colorectal cancer patients after curative resection

BACKGROUND

The advanced lung cancer inflammation index (ALI), which comprehensively evaluates the patient body composition and inflammation/nutritional status, is reportedly associated with the patient outcome in lung cancer. However, the clinical significance in colorectal cancer (CRC) patients after curative resection remains unclear.

METHODS

A total of 813 CRC patients after curative resection between April 2005 and June 2019 in a single institution were retrospectively enrolled. The association of the preoperative ALI (calculated as follows: body mass index × albumin value/neutrophil-to-lymphocyte ratio) with clinicopathological factors, postoperative complications, and survival was analyzed.

RESULTS

A low ALI was significantly associated with male gender, older age, a higher depth of tumor invasion, progressed TNM stage, and preoperative carcinoembryonic antigen (CEA) positivity. Both postoperative complications and severe complications occurred more frequently in the ALI-low group than in the ALI-high group (P < .001 and P < .001, respectively), especially postoperative complications in stage III patients (P < .001) and severe complications in stages II and III patients (P = .024 and P = .004, respectively). In addition, a low ALI was an independent predictor of a poor overall survival (hazard ratio: 2.30, 95% confidence interval: 1.52-3.50, P < .001) and relapse-free survival (hazard ratio: 1.73, 95% confidence interval: 1.22-2.44, P = .002), especially in older patients, and in patients without lymph node metastasis or severe postoperative complications.

CONCLUSION

This study suggests that preoperative ALI may serve as a novel independent predictive index for severe postoperative complications and recurrence in CRC patients after curative resection.

Molecular differences between lymph nodes and distant metastases compared with primaries in colorectal cancer patients

Lymph nodes (LNs) and distant metastases can arise from independent subclones of the primary tumor. Herein, we characterized the molecular landscape and the differences between LNs, distant metastases and primary colorectal cancers (CRCs). Samples were analyzed using next generation sequencing (NGS, MiSeq on 47 genes, NextSeq on 592 genes) and immunohistochemistry. Tumor mutational burden (TMB) was calculated based on somatic nonsynonymous missense mutations, and microsatellite instability (MSI) was evaluated by NGS of known MSI loci. In total, 11,871 samples were examined, comprising primaries (N = 5862), distant (N = 5605) and LNs metastases (N = 404). The most frequently mutated genes in LNs were TP53 (72%), APC (61%), KRAS (39%), ARID1A (20%), PIK3CA (12%). LNs showed a higher mean TMB (13 mut/MB) vs distant metastases (9 mut/MB, p < 0.0001). TMB-high (≥17mut/MB) and MSI-H (8.8% and 6.9% vs 3.7%, p < 0.001 and p = 0.017, respectively) classifications were more frequent in primaries and LNs vs distant metastases (9.5% and 8.8% vs 4.2%, p < 0.001 and p = 0.001, respectively). TMB-high is significantly more common in LNs vs distant metastases and primaries (P < 0.0001), regardless MSI-H status. Overall, LNs showed significantly different rates of mutations in APC, KRAS, PI3KCA, KDM6A, and BRIP1 (p < 0.01) vs primaries, while presenting a distinct molecular profile compared to distant metastases. Our cohort of 30 paired samples confirmed the molecular heterogeneity between primaries, LNs, and distant metastases. Our data support the hypothesis that lymphatic and distant metastases harbor different mutational landscape. Our findings are hypothesis generating and need to be examined in prospective studies.

Time trial of dry box laparoscopic surgical training improves laparoscopic surgical skills and surgical outcomes

INTRODUCTION

The present study assessed the utility of a dry box time trial during laparoscopic surgical training to improve laparoscopic surgical skills and surgical outcomes.

METHODS

In a monthly time trial, surgeon trainees twice completed a set task that involved grasping a suture, aligning a needle with a needle holder, passing the suture, making three knots, and cutting the two tails of the suture. The mean suturing time was then analyzed. To assess the utility of this time trial, we analyzed the short-term outcomes of patients with stage I to III colon cancer who had undergone laparoscopic colectomy before and after the introduction of the time trial.

RESULTS

The monthly time trial was introduced in October 2018, and 52 surgeon trainees participated in the trials examined in this study. Within 6 months of the program's introduction, the mean suturing time had significantly declined to less than 70% of the time trial, while the standard deviations had declined to less than 30%. In comparisons of the short-term outcomes of laparoscopic colon cancer surgery before (n = 49) and after (n = 46) the introduction of the time trial, the operative time tended to decline (P = .074) after the introduction of the time trial, and blood loss was significantly reduced (P = .018). The rate of postoperative complications was similar before and after the introduction.

CONCLUSION

Regular time trials of laparoscopic surgical suture training using a dry box can be useful for improving laparoscopic surgical skills and surgical outcomes. Moreover, time trials can keep trainees motivated.

Random survival forests identify pathways with polymorphisms predictive of survival in KRAS mutant and KRAS wild-type metastatic colorectal cancer patients

KRAS status serves as a predictive biomarker of response to treatment in metastatic colorectal cancer (mCRC). We hypothesize that complex interactions between multiple pathways contribute to prognostic differences between KRAS wild-type and KRAS mutant patients with mCRC, and aim to identify polymorphisms predictive of clinical outcomes in this subpopulation. Most pathway association studies are limited in assessing gene–gene interactions and are restricted to an individual pathway. In this study, we use a random survival forests (RSF) method for identifying predictive markers of overall survival (OS) and progression-free survival (PFS) in mCRC patients treated with FOLFIRI/bevacizumab. A total of 486 mCRC patients treated with FOLFIRI/bevacizumab from two randomized phase III trials, TRIBE and FIRE-3, were included in the current study. Two RSF approaches were used, namely variable importance and minimal depth. We discovered that Wnt/β-catenin and tumor associated macrophage pathway SNPs are strong predictors of OS and PFS in mCRC patients treated with FOLFIRI/bevacizumab independent of KRAS status, whereas a SNP in the sex-differentiation pathway gene, DMRT1, is strongly predictive of OS and PFS in KRAS mutant mCRC patients. Our results highlight RSF as a useful method for identifying predictive SNPs in multiple pathways.

RNA-Binding Protein Polymorphisms as Novel Biomarkers to Predict Outcomes of Metastatic Colorectal Cancer: A Meta-analysis from TRIBE, FIRE-3, and MAVERICC

RNA-binding proteins (RBPs) regulate many posttranscriptional cellular activities. Accumulating evidence suggests associations between RBPs with colonic tumorigenesis and chemosensitivity. We investigated the prognostic and predictive values of SNPs of genes encoding RBPs in metastatic colorectal cancer (mCRC), using clinical and genomic data from three randomized clinical trials of standard first-line chemotherapy for mCRC (TRIBE, FIRE-3, and MAVERICC). Genomic DNA extracted from blood samples was genotyped using an OncoArray. We tested 30 candidate SNPs of 10 major RBP-related genes with additive models. Prognostic values were estimated by meta-analysis approach. Treatment-by-SNP interactions were tested to estimate predictive values for targeted drugs and cytotoxic backbone chemotherapies. This study included 884 patients. The meta-analysis revealed prognostic values of LIN28B rs314277 [HR, 1.26; 95% confidence interval (CI), 1.06-1.49, P = 0.005, FDR-adjusted P = 0.072 for overall survival (OS)] and LIN28B rs314276 (HR, 1.25; 95% CI, 1.08-1.44, P = 0.002, FDR-adjusted P = 0.062 for OS). Although some SNPs showed potentially predictive values, these associations were not confirmed after FDR adjustment. In conclusion, the results of this study are warranting additional studies to provide the evidence that RBP-related SNPs may be associated with the prognosis of patients with mCRC treated with standard first-line chemotherapies. In addition, further studies are warranted to study the predictive value.

Precision medicine for adjuvant chemotherapy of resected colorectal cancer

Colorectal cancer (CRC) is the most common cancer and the second leading cause of cancer death in Japan. Surgical resection is the only curative option for localized disease. However, undetectable micrometastases remaining after curative surgery may cause disease recurrence. Adjuvant chemotherapy aims to eradicate these micrometastases to improve the cure rate. Unfortunately, few reliable prognostic and predictive markers are available that identify patients at high risk for CRC during early-stage disease. However, promising biomarkers may become available in the near future. Such biomarkers provide information for stratifying a patient's risk and for selecting the optimal treatment. Here, we provide an overview of current relevant prognostic and predictive biomarkers applicable to adjuvant treatment of early-stage CRC and focus on the future of this field.

The impact of ARID1A mutation on molecular characteristics in colorectal cancer

BACKGROUND

ARID1A is a key subunit of the SWItch/Sucrose Non-Fermentable (SWI/SNF) complex which regulates dynamic repositioning of nucleosomes to repair DNA damage. Only small pilot studies have evaluated the role of ARID1A mutation in colorectal cancer (CRC). The aim of the present study was to explore the potential impact of ARID1A mutation on clinicopathological and molecular characteristics in CRC.

METHODS

We used integrated data sets of 7978 CRC cases (one data set from a clinical laboratory improvement amendments [CLIA]-certified laboratory and three independent published data sets). The associations of ARID1A mutation with molecular characteristics including immune profile (the status of microsatellite instability [MSI], tumour mutational burden [TMB], programmed death ligand 1 [PD-L1] and estimated infiltrating immune cells), clinicopathological features and related pathways were analysed using next-generation sequencing, RNA sequencing and immunohistochemistry.

RESULTS

ARID1A mutant samples had more genomically unstable tumour features (MSI-high and TMB-high) and exhibited more characteristics of a T-cell-inflamed microenvironment (PD-L1 expression and high estimated infiltrating cytotoxic T lymphocytes [CTLs]) than ARID1A wild-type samples in the discovery and validation cohorts. Even ARID1A mutant samples without MSI-high status were TMB-high, had high levels of PD-L1 expression and high estimated infiltrating CTLs. ARID1A mutations were more common with right-sided primary and earlier stage tumours. ARID1A mutant tumours mainly had co-occurring gene mutations related to chromatin modifying, DNA repair, WNT signalling and epidermal growth factor receptor inhibitor resistance pathways, and ARID1A mutations strongly regulated DNA repair pathways. Key genes for chemotherapy/radiotherapy sensitivity were suppressed in ARID1A mutant samples.

CONCLUSIONS

Our findings may provide novel insights to develop individualised approaches for treatment of CRC based on ARID1A mutation status.

Preoperative C-reactive protein-to-albumin ratio and clinical outcomes after resection of colorectal liver metastases

PURPOSE

Accumulating evidence suggests that the inflammatory tumor microenvironment can potentiate tumor progression and metastasis. The C-reactive protein-to-albumin ratio (CAR) is a novel inflammation-based prognostic score. This study was performed to examine the associations of the preoperative CAR with clinical outcomes in patients with colorectal liver metastases (CRLM) after curative resection.

METHODS

We retrospectively assessed the preoperative CAR in 184 patients who underwent curative resection for CRLM from November 2001 to January 2018 at Kumamoto University (Kumamoto, Japan). The optimal cutoff level of the preoperative CAR was determined by survival classification and regression tree (CART) analysis. We compared clinicopathological factors and prognoses between the high-CAR and low-CAR groups. A Cox proportional hazards model was used to calculate hazard ratios (HRs), controlling for potential confounders.

RESULTS

A higher preoperative CAR was associated with worse overall survival (OS) (p < 0.0001) and recurrence-free survival (RFS) (p = 0.003). Applying survival CART analysis, the high-CAR group comprised 33 patients (17.9%). In the multivariate analyses, a high CAR was independently associated with shorter OS (HR, 2.82; 95% confidence interval, 1.63-4.72; p = 0.0004) and RFS (HR, 1.62; 95% confidence interval, 1.02-2.49; p = 0.040). A high CAR was associated with a large tumor size, high serum carcinoembryonic antigen and carbohydrate antigen 19-9 levels, high intraoperative blood loss, and more postoperative complications.

CONCLUSION

A high preoperative CAR is associated with shorter OS and RFS and might serve as a prognostic marker for patients with CRLM after curative resection.

Comprehensive Genomic Profiling of Gastroenteropancreatic Neuroendocrine Neoplasms (GEP-NENs)

PURPOSE

GEP-NENs are rare malignancies with increasing incidence. Their molecular characteristics are still undefined. We explored the underlying biology of GEP-NENs and the differences between gastrointestinal (GI) and pancreatic (PNEN), high-grade (HG), and low-grade (LG) tumors.

EXPERIMENTAL DESIGN

GEP-NENs were analyzed using next-generation sequencing (NGS; MiSeq on 47 genes, NextSeq on 592 genes), IHC, and in situ hybridization. Tumor mutational burden (TMB) was calculated on the basis of somatic nonsynonymous missense mutations, and microsatellite instability (MSI) was evaluated by NGS of known MSI loci.

RESULTS

In total, 724 GEP-NENs were examined: GI (N = 469), PNEN (N = 255), HG (N = 135), and LG (N = 335). Forty-nine percent were female, and median age was 59. Among LG tumors, the most frequently mutated genes were ATRX (13%), ARID1A (10%), and MEN1 (10%). HG tumors showed TP53 (51%), KRAS (30%), APC (27%), and ARID1A (23%). Immune-related biomarkers yielded a lower prevalence in LG tumors compared with HG [MSI-H 0% vs. 4% (P = 0.04), PD-L1 overexpression 1% vs. 6% (P = 0.03), TMB-high 1% vs. 7% (P = 0.05)]. Compared with LG, HG NENs showed a higher mutation rate in BRAF (5.4% vs. 0%, P < 0.0001), KRAS (29.4% vs. 2.6%, P < 0.0001), and PI3KCA (7% vs. 0.3%, P < 0.0001). When compared with GI, PNEN carried higher frequency of MEN1 (25.9% vs. 0.0%, P < 0.0001), FOXO3 (8.6% vs. 0.8%, P = 0.005), ATRX (20.6% vs. 2.0%, P = 0.007), and TSC2 (6.3% vs. 0.0%, P = 0.007), but lower frequency of mutations in APC (1.0% vs. 13.8%, P < 0.0001).

CONCLUSIONS

Significant molecular differences were observed in GEP-NENs by tumor location and grade, indicating differences in carcinogenic pathways and biology.

Fibrosis-4 Index, a Noninvasive Fibrosis Marker, Predicts Survival Outcomes After Hepatectomy for Colorectal Cancer Liver Metastases

BACKGROUND

Liver fibrosis influences liver regeneration and surgical outcomes, and several noninvasive models based on laboratory data have been developed to predict liver fibrosis. This study was performed to determine whether the Fibrosis-4 (FIB-4) index, a noninvasive fibrosis marker, can predict the prognosis in patients with colorectal liver metastases (CRLM) undergoing hepatectomy.

METHODS

This retrospective study involved 193 consecutive patients with CRLM who underwent hepatectomy. The FIB-4 index was calculated by laboratory data and age before hepatectomy and before preoperative chemotherapy. The FIB-4 cut-off was determined using survival classification and regression tree analysis. Patients were divided into two groups (high and low FIB-4 index), and post-hepatectomy overall survival (OS) and recurrence-free survival (RFS) were investigated.

RESULTS

In total, 193 patients were evaluated. Chemotherapy before hepatectomy was performed in 105 (54.4%) patients. A high FIB-4 index (> 2.736) was found in 39 (20.2%) patients. OS was significantly shorter in patients with a high FIB-4 index than those with a low FIB-4 index in the univariate (45.9 vs. 74.4 months, log-rank p = 0.007) and multivariate analysis (hazard ratio 2.28, 95% confidence interval 1.39-3.74; p = 0.001). Among patients who received chemotherapy before hepatectomy, those with a high FIB-4 index had significantly shorter RFS (6.9 vs. 45.3 months, log-rank p = 0.047) and OS (23.9 vs. 55.0 months, log-rank p = 0.003) than those with a low FIB-4 index. This association was also confirmed by multivariate analysis (hazard ratio 4.28, 95% confidence interval 1.46-12.6; p = 0.008).

CONCLUSION

Both the preoperative and prechemotherapy FIB-4 index can predict long-term outcomes after hepatectomy in patients with CRLM.

Ongoing 5-year+ survival after multiple metastasectomies, followed by CAPOX plus bevacizumab, for metastatic colorectal cancer

Background

Advancements in chemotherapy for metastatic colorectal cancer (mCRC) have improved long-term outcomes, and median survival currently exceeds 30 months. The recommended treatment for mCRC is multidisciplinary, including a combination of surgical resection and chemotherapy. In this study, we report the case of a patient who has survived for more than 5 years after an initial diagnosis of mCRC while undergoing first-line chemotherapy and six repeat metastasectomies.

Case presentation

A 55-year-old man was diagnosed at our hospital with sigmoid colon cancer and hepatic metastasis. We performed laparoscopic sigmoidectomy and hepatic segmentectomy (segment 5 [S5] and S8). After resecting the primary tumor and liver metastasis, other metastases were found. Together with perioperative chemotherapy (CAPOX + bevacizumab), we performed repeated metastasectomies for liver metastasis (S4 and S7), pulmonary S1 metastasis, aortic lymph node metastasis, and right adrenal metastasis. With six metastasectomies, the patient has survived for more than 5.5 years.

Conclusions

Multidisciplinary treatment extends survival and improves the quality of life in patients with mCRC. Planned surveillance after metastasectomy may also be necessary to promote the early detection of recurrence in these patients.

Total Lesion Glycolysis Ratio in Positron Emission Tomography/Computed Tomography Images During Neoadjuvant Chemotherapy Can Predict Pathological Tumor Regression Grade and Prognosis in Patients with Locally Advanced Squamous Cell Carcinoma of the Esophagus

BACKGROUND

The usefulness of quantitating tumor lesion glycolysis (TLG) from ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) findings as a tool for determining the effect of neoadjuvant chemotherapy (NAC) in esophageal squamous cell carcinoma (ESCC) has not yet been established.

METHODS

The cohort of this retrospective study comprised 46 patients who had undergone NAC and subsequent esophagectomy for locally advanced ESCC between January 2008 and December 2017. PET/CT was conducted before and after NAC to assess its therapeutic effect. Associations between changes in TLG values during NAC and clinicopathological findings, pathological tumor regression grade (TRG), and prognosis were assessed.

RESULTS

Most patients received two courses of DCF (Docetaxel, Cisplatin, and Fluorouracil) as NAC. The mean TLG value of the primary tumor decreased significantly after NAC. The median follow-up period was 41 months. The Kaplan-Meier method, analyzed by log-rank test, showed that low TLG ratio (≤ 0.4) and low SUV_max ratio (≤ 0.6) were associated with favorable survival outcomes (P = 0.0073 and P = 0.032, respectively). Univariate and multivariate analysis revealed that TLG ratio and achievement of pathological cure were independent prognostic factors for overall survival. TLG ratio was also associated with pathological TRG (TRG 0-1a vs 1b-3) (P = 0.0016).

CONCLUSIONS

TLG ratio before and after NAC is clinically useful in predicting both histological response and survival outcome after NAC and subsequent esophagectomy in patients with ESCC.

Comprehensive gene expression analysis of IDH1/2 mutant biliary cancers (BC)

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Background: Isocitrate dehydrogenases (IDH) mutations (mut) identify a distinct subtype of BC that has yet to be fully characterized. We recently showed that IDH1/2 mutant (mIDH) BC harbor specific gene alterations involving chromatin remodeling and DNA repair, and a differential immune markers profile compared to other mIDH GI tumors. Here we aim to further dissect the molecular profile of mIDH BC through a comprehensive gene expression profiling analysis. Methods: 524 BC samples (303 intrahepatic cholangiocarcinoma, IHCC, 67 extrahepatic cholangiocarcinoma, EHCC, 141 gallbladder, 13 unspecified) collected between February to December of 2019 were included. Samples were analyzed using NextGen DNA sequencing (NextSeq, 592 gene panel), whole transcriptome RNA sequencing (NovaSeq) and immunohistochemistry (Caris Life Sciences, Phoenix, AZ). EBseq was used to identify differentially expressed genes in mIDH vs wild type (WT) tumors with control for FDR ( Q < 0.2). Pathway and functional enrichment analysis was performed using g:Profiler and Enrichr. Results: mIDH frequency in our cohort was 11.4% (60/524), with higher prevalence of IDH1 mut (8.8%). IHCC showed the highest mut prevalence: IDH1 13.5%, IDH2 4.6%. mIDH was more common in females ( P = 0.0036). A total of 774 genes were significantly differentially expressed between mIDH and WT: 582 underexpressed (Fold change, FC: 0.025~0.699); 192 overexpressed (FC: 1.43~3.3). Pathway enrichment showed a significant decrease of gene expression in cytokine-cytokine receptor interaction ( Q = 0.002) and inflammatory response genes ( Q = 0.005) in mIDH. Interferon-γ- and PD1 signaling-related genes expression was significantly lower in mIDH vs WT ( Q = 0.02) including IFNG (FC 0.32), NKG7 (FC 0.36), CD8B (FC 0.37), BATF (FC 0.40), PD1 (FC 0.53), SLAMF6 (FC 0.55) and PD-L2 (FC 0.60). Wnt and cadherin signaling were also enriched for altered expression in several genes in mIDH BC ( Q = 3.86e-7 and < 0.00001, respectively). Conclusions: To our knowledge, this is the largest and most extensive gene expression profiling study focused on mIDH BC. Our data show for the first time a distinct gene expression profile characterizing mIDH tumors which display significant downregulation of inflammatory response pathways and immune-related genes. These findings contribute to further the understanding of mIDH BC and may inform the future development of rational combination therapies.

IgG4-related disease presenting as a submucosal tumor of the stomach resected with laparoscopic endoscopic cooperative surgery: a case report

Background

IgG4-related disease (IgG4-RD) is an immune-mediated disorder in which abundant IgG4-positive plasma cells infiltrate affected organs. There have been reported four cases of probable IgG4-RD presenting as a submucosal tumor of the stomach. We herein report the first case of definite IgG4-RD presenting as a submucosal tumor of the stomach resected with laparoscopic endoscopic cooperative surgery (LECS).

Case presentation

A 70-year-old woman with a 6-year history of autoimmune pancreatitis was referred to our department because a 15-mm submucosal tumor in the greater curvature of the lower part of the stomach had been identified via upper gastrointestinal endoscopy. Endoscopic ultrasonography showed a 10-mm low-echoic lesion derived from the submucosal layer of the stomach. A fine-needle aspiration biopsy was attempted, but the tumor was too hard for sampling. F-fluorodeoxyglucose (FDG) positron emission tomography showed an FDG uptake, suggesting a possibility of malignant disease. As the diagnosis could not be confirmed, LECS for both the diagnosis and curative treatment was performed. A histopathological examination showed a tumor with IgG4-positive lymphoplasmacytic infiltration and fibrosis. The ratio of IgG4+/IgG+ lymphoplasmacytic cells was > 80%. A laboratory examination showed elevation of the serum IgG4 levels preoperatively. Thus, the final diagnosis was IgG4-RD of the stomach. No recurrence was observed within 1 year after surgery.

Conclusions

We encountered a case of definite IgG4-RD presenting as a gastric SMT in which a correct diagnosis was achieved by a minimally invasive LECS technique. IgG4-RD may present as a gastric lesion and should be taken into consideration as a differential diagnosis.

Postoperative complications are associated with poor survival outcome after curative resection for colorectal cancer: A propensity-score analysis

OBJECTIVE

We retrospectively evaluated the impact of postoperative complications on long-term outcomes after curative resection for colorectal cancer (CRC), using propensity-score analysis (PSA).

PATIENTS AND METHODS

We reviewed data from 673 consecutive patients with stage I to III CRC, who underwent curative resections between 2005 and 2017. Patients were divided into the complication group (Clavien-Dindo [CD] grade ≥ 3) and the control group (others). We performed PSA to obtain unbiased estimates of the effects of the oncological background on each outcome.

RESULTS

We matched for sex, age, American Society of Anesthesiologists grade, location (right colon/left colon/rectum), histology (tub1/tub2/por), pathological tumor depth, and lymph node metastases. Eighty-five patients (12.6%) developed postoperative complications with CD grade ≥ 3. After PSA, 81 patients were included in each group. The complication group showed significantly worse relapse-free survival (RFS) than the control group (5-year RFS rate: 62% vs 77%; P = .047). In multivariate analysis with inverse probability of treatment weights, the complication group had a higher risk of relapse or death than the control group (hazard ratio: 2.08, 95% confidence interval:1.3-3.3; P = .018).

CONCLUSIONS

Postoperative complications (CD grade ≥ 3) could cause poor long-term outcomes in patients with stage I to III CRC; their presence requires appropriate adjuvant chemotherapy and follow-up.

12-Chemokine signature, a predictor of tumor recurrence in colorectal cancer

Tertiary lymphoid structures (TLSs) provide an immunological antineoplastic effect. Recent evidences link a unique 12-chemokine (CCL2, -3, -4, -5, -8, -18, -19, -21, CXCL9, -10, -11, -13) signature status from tumor tissue and the TLS expression. However, the potential significance of 12-chemokine signature status for clinical use is unknown. We aimed to evaluate the association of 12-chemokine signature status with patient outcomes in colorectal cancer (CRC). We used integrated data of resected 975 CRC cases within three independent cohorts from France, Japan and the United States (GSE39582, KUMAMOTO from Kumamoto university hospital and TCGA). The association of 12-chemokine signature status with clinicopathological features, patient outcome, TLS expression status and key tumor molecular features was analyzed. Patients with low 12-chemokine signature status had a significant shorter relapse-free survival in discovery cohort (HR: 1.61, 95% CI: 1.11-2.39, p = 0.0123), which was confirmed in validation cohort (HR: 3.31, 95% CI: 1.33-10.08, p = 0.0087). High 12-chemokine signature status had significant associations with right-sided tumor, high tumor-localized TLS expression, BRAF mutant, CIMP-high status and MSI-high status. Furthermore, RNA-seq based analysis showed that high 12-chemokine signature status was strongly associated with inflammation-related, immune cells-related and apoptosis pathways (using gene set enrichment analysis), and more tumor-infiltrating immune cells, such as cytotoxic T lymphocytes and myeloid dendritic cells (using MCP-counter analysis). We investigated a promising effect of 12-chemokine signature status in CRC patients who underwent resection. Our data may be helpful in developing novel immunological treatment strategies for CRC.

A polymorphism within the R-spondin 2 gene predicts outcome in metastatic colorectal cancer patients treated with FOLFIRI/bevacizumab: data from FIRE-3 and TRIBE trials

BACKGROUND

Through enhancement of the Wnt signalling pathway, R-spondins are oncogenic drivers in colorectal cancer. Experimental data suggest that the R-spondin/Wnt axis stimulates vascular endothelial growth factor (VEGF)-dependent angiogenesis. We therefore hypothesise that variations within R-spondin genes predict outcome in patients with metastatic colorectal cancer (mCRC) treated with upfront FOLFIRI and bevacizumab.

PATIENTS AND METHODS

773 patients with mCRC enrolled in the randomised phase III FIRE-3 and TRIBE trials and receiving either FOLFIRI/bevacizumab (training and validation cohorts) or FOLFIRI/cetuximab (control group) were involved in this study. The impact of six functional single-nucleotide polymorphisms (SNPs) within the R-spondin 1-3 genes on outcome was evaluated.

RESULTS

RAS and KRAS wild-type patients harbouring any G allele of the RSPO2 rs555008 SNP had a longer overall survival compared with those having a TT genotype in both the training (FIRE-3) and validation (TRIBE) cohorts (29.0 vs 23.6 months, P = 0.009 and 37.8 vs 19.4 months, P = 0.021 for RAS wild-type patients and 28.4 vs 22.3 months, P = 0.011 and 36.0 vs 23.3 months, P = 0.046 for KRAS wild-type patients). Conversely, any G allele carriers with KRAS and RAS mutant tumours exhibited a shorter progression-free survival compared with TT genotype carriers, whereas the results were clinically more evident for KRAS mutant patients in both the training and validation cohorts (8.1 vs 11.2 months, P = 0.023 and 8.7 vs 10.3 months, P = 0.009).

CONCLUSION

Genotyping of the RSPO2 rs555008 polymorphism may help to select patients who will derive the most benefit from FOLFIRI/bevacizumab dependent on (K)RAS mutational status.

Wives as Key Persons Positively Impacting Prognosis for Male Patients Undergoing Esophagectomy for Esophageal Cancer: A Retrospective Study from a Single Japanese Institute

BACKGROUND

Identification of a key person for supporting patients with activities of daily living after esophagectomy can contribute to patients' nutrition, rehabilitation, mental status, and determination of treatments for cancer. It may also affect the patients' prognostic outcomes.

PATIENTS AND METHODS

This retrospective study included 504 patients who underwent three-incisional esophagectomy for esophageal cancer between June 2005 and June 2018 at the Kumamoto University Hospital. The association between the type of key person identified and overall survival (OS) was investigated. The impact of the key person on postoperative nutrition and survival after recurrence was also examined.

RESULTS

Clinical backgrounds in patients with and without wife as their key person were equivalent. OS among male patients who identified their wife as their key person was significantly better than that in those without their wife as key person (P = 0.0035). Cox regression analysis showed that absence of a wife was an independent risk factor for worse survival outcomes (hazard ratio, 0.62; 95% confidence interval, 0.393-0.987; P = 0.044) along with age, clinical stage, severe postoperative morbidity, and pathological curability. Presence of a wife did not affect postoperative nutritional status. Incidence of death due to other causes and OS after recurrence were better in male patients with a wife than in those without; however, this difference was not significant.

CONCLUSIONS

Among males with esophageal cancer, their wives may be a significant contributor to extension of survival after surgery, via various support mechanisms.

Molecular landscape of gastric cancer (GC) harboring mutations of histone methyltransferases

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Background: Alteration of histone modifications participating in transcription and genomic instability, has been recognized as an important role in tumorigenesis. Aberrant expression of histone-lysine N-methyltransferase 2 ( KMT2) family, which methylate histone H3 on lysine 4, is significantly correlated with poor survival in GC. Understanding how gene mutations of KMT2 family interact to affect cancer progression could lead to new treatment strategies. Methods: A total of 1,245 GC were analyzed using next-generation sequencing (NGS) and immunohistochemistry (IHC; Caris Life Sciences, Phoenix, AZ). Tumor mutational burden (TMB) was calculated based on somatic nonsynonymous mutations, and MSI status was evaluated by a combination of IHC, fragment analysis and NGS. PD-L1 status was analyzed by IHC (SP142). Gene fusions were detected by Archer (N = 59) or whole-transcriptome sequencing (N = 129). Results: The overall mutation rate of genes in KMT2 family was 10.6% ( KMT2A: 1.7 %, KMT2C: 4.7%, KMT2D: 7.1%). Overall, the mutation rates were significantly higher in KMT2-mutated (MT) GC than KMT2-wild type (WT) GC, except for TP53 (43% vs 63%, p < .0001). Interestingly, among the genes with significant higher mutation rates in KMT2-MT GC, 28% (21/76) of them were related to DNA damage repair (including BRCA1/ 2, RAD50) and 33% (25/76) of them were related to chromatin remodeling (including ARID1A/ 2, SMARCA4). Overexpression of HER2, amplifications of KRAS, CDK6 and HER2 were significant lower, while PCM1 and BCL3 amplifications were significant higher in KMT2-MT, compared to KMT2-WT GC ( p < .05). Significantly higher prevalence of TMB-high ( > 17mut/MB) (49% vs 3%), MSI-H (53% vs 2%), and PD-L1 overexpression (20% vs 7%) were present in KMT2-MT GC, compared to KMT2-WT GC ( p < .001). The rates of fusions involving ARHGAP26 (19% vs 3%, p < .01)and RELA (29% vs 0%, p < .0001) were significantly higher in KMT2-MT than those in KMT2-WT GC. Conclusions: This is the largest study to investigate the distinct genomic landscape between KMT2-MT and WT GC. Our data indicates that KMT2-MT GC patients could potentially benefit from agents targeting DNA damage repair and immunotherapy, which warrants further in-vitro and in-vivo investigation.

Polymorphisms of genes encoding for regulatory proteins in the coagulation cascade to predict outcome for stage II and III colon cancer

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Background: In cancer patients, an activated coagulation cascade might promote tumor cell dissemination. There are preliminary data suggesting that fibrinogen in combination with platelets can build a meshwork that entraps cancer cells enabling them to escape from immunosurveillance. We therefore hypothesize that variations in genes encoding for regulatory proteins within the coagulation pathway may predict outcome in patients with stage II and III colon cancer. Methods: The impact of three functional single nucleotide polymorphisms (SNPs) within the FGB, SERPINC1 and ITGA2B genes on time to recurrence and overall survival was evaluated in 209 patients with stage II and III colon cancer. Genomic DNA was isolated from formalin-fixed paraffin embedded tissue and the SNPs were analyzed by PCR-based direct sequencing. Results: Baseline characteristics were as follows: median age = 70y (19-91); female/male ratio = 42.8% / 57.2%; 111 patients had stage II, and 98 stage III colon cancer. The FGB rs4220 SNP showed significant association with recurrence rate in the overall population. Patients harboring any A allele had a higher 3-years recurrence rate compared to those with a G/G genotype (28% vs 17%) in both univariate (HR 1.83, 95% confidence interval (CI) 0.99-3.36, p = 0.048) and multivariate analyses (HR 1.94, 95% CI 1.05-3.57, p = 0.034). This trend was most evident among pts with stage II and especially the subgroup of high-risk stage II colon cancer. Again, A allele carriers had a higher 3-years recurrence rate compared to those having a G/G genotype (24% vs 10% and 44% vs 15% respectively) in both univariate (HR 3.32, 95% CI 1.26-8.74, p = 0.010 and HR 5.34, 95% CI 1.38-20.68, p = 0.006) and multivariate analyses (HR 3.34, 95% CI 1.27-8.78, p = 0.015 and HR 5.44, 95% CI 1.40-21.15, p = 0.015). Conclusions: Here, we demonstrate that the FGB polymorphism rs4220 might serve as a prognostic biomarker in stage II colon cancer. Assessment of FGB rs4220 might help us to identify those stage II colon cancer patients who will derive the most benefit from adjuvant chemotherapy.

Comprehensive molecular profiling of IDH1/2 mutant biliary cancers (BC)

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Background: Isocitrate dehydrogenases (IDH) play a key role in energetic metabolism and IDH mutations (mut) promote oncogenesis via epigenetic and genetic changes. Data addressing the molecular contexture of IDH1/2 mut in BC are lacking. We aimed to characterize the molecular profile of IDH1/2 mutant (mIDH) GI cancers with a focus on BC. Methods: 27954 GI cancer samples collected between August 2000 and July 2019 were included: 2057 BC (1159 ICC, 277 extrahepatic CC, 573 gallbladder, 48 unspecified CC), 13807 colorectal, 4183 gastric/esophageal, 3060 other. Samples were analyzed using NextGen DNA sequencing, in situ hybridization, RNA sequencing and immunohistochemistry (Caris Life Sciences, Phoenix, AZ). Tumor mutational burden (TMB) was calculated based on somatic nonsynonymous missense mut. MMR/MSI status was evaluated by a combination of IHC, Fragment Analysis and NGS. Results: mIDH frequency in BC was 10.3% (211/2057), with higher prevalence of IDH1 mut (8.2%). ICC showed the highest mut prevalence: IDH1 13.5%, IDH2 4%. Mut rates in other GI cancers types were < 1%, except for HCC (1.9%, 11/582) and small bowel (1.1%, 8/736). When compared to IDH wild type (WT), mIDH BC showed lower mut rates in TP53 (13 vs 43%), KRAS (8 vs 19%), CDKN2A (1 vs 9%), and SMAD4 (0 vs 9%), whereas PBRM1 mut were higher (14 vs 5%) ( P < .001 for all comparisons). There was a trend towards higher frequency of ARID1A and BAP1 in mIDH BC. HER2 expression and amplification rates were lower in mIDH vs WT BC (0.5 vs 3%, P = .048 and 0 vs 6%, P = .002). FGFR2 fusion was detected in 7% of WT vs 2% of mIDH BC. mIDH BC showed a lower TMB (0.7 vs 3.7%, P = .048) and a trend for lower MSI rates (0.6 vs 3%, P = .06) vs WT BC. Conversely, IDH mut were associated with higher TMB and MSI ( P < .001) and higher PD-L1 expression in other GI cancers. Conclusions: This is the largest and most extensive profiling study to investigate the molecular makeup of mIDH BC and GI tumors. Our data show distinct gene alteration patterns characterizing mIDH BC, involving genes related to chromatin remodeling and DNA repair, and a differential expression of immune related markers compared to other mIDH GI tumors. These findings can contribute to the development of rational combination therapies and to improved patient selection in the future.

Genetic variants in R-Spondin/RNF43 complex and gene expression levels to predict efficacy of cetuximab (cet) in patients (pts) with metastatic colorectal cancer (mCRC): Data from the FIRE-3 phase III trial

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Background: Wnt signaling deregulation is a primary driver of colorectal carcinogenesis. RNF43 is a key suppressor of Wnt activation while R-Spodin inhibits RNF43 activity. RNF43 mutations are associated with the serrated neoplasia pathway, BRAF mutation and MSI. We hypothesized that genetic variants in the R-Spodin/RNF43 complex and corresponding genes expression levels may predict cetuximab efficacy in mCRC pts. Methods: Genomic DNA from blood samples of pts enrolled in the randomized FIRE-3 trial was genotyped through the OncoArray, a custom array manufactured by Illumina. The impact on outcome of 17 functional SNPs within RNF43/ ZNRF3, LGR4/5 and RSPO1/2/3 was analyzed in 129 pts treated with first-line FOLFIRI/cet and 107 pts treated with FOLFIRI/bevacizumab (bev). Gene expression levels were measured from tumor tissue samples from 102 pts in the cet arm by HTG EdgeSeq Oncology Biomarker Panel. False discovery rate (FDR) for gene expression analysis was computed using the Benjamini-Hochberg approach (significant Q < 0.1). Results: In the cet cohort, pts with the C/C genotype of ZNRF3 rs132531 had significantly shorter overall survival compared to any T allele carriers (mOS: 20.3 vs 52 mo) in both univariable (HR 3.61, 95% CI 1.65-7.88, P < .001) and multivariable analysis (adjusted P = .01). Conversely, RSPO1 rs4652964 any G allele carriers showed increased tumor response (TR) rates compared to the A/A genotype (83 vs 66 %, P = .04). These associations were not observed in bev arm. Lower gene expression levels of RNF43 were associated with shorter PFS in pts with right-sided tumors receiving FOLFIRI/cet ( P = .006, Q < 0.1). RSPO1 expression levels were also associated with TR in the same subgroup (70 vs 10% in high vs low; P = .001, Q < .05). RNF43 expression was associated with TR in pts with left-sided tumors (82% in high vs 58% in low, P = .014, Q = 0.1). Conclusions: Our results provide the first evidence that germline polymorphisms and tumor gene expression levels of RNF43/ ZNRF3 and RSPO1 may have a predictive value in mCRC pts receiving first-line cetuximab-based treatment and contribute to modulate anti-EGFRs activity.

Variation in genetic polymorphisms and gene expression of HLA-E to predict outcomes in metastatic colorectal cancer (mCRC) patients (pts) treated with first-line FOLFIRI/cetuximab: Data from the phase III FIRE-3 trial

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Background: HLA-E is an MHC Class I antigen which inhibits NK cell activity by binding to CD94 receptor. Overexpression of HLA-E on crc cells is associated with poor prognostic outcomes and has recently been associated with microsatellite instability. As cet enhances NK cell activity which is dependent on HLAE, this study aims to assess whether differences in HLAE gene expression and polymorphisms lead to different outcomes. Methods: Genomic DNA from blood samples of pts treated with first-line FOLFIRI-cetuximab (cet, n = 129) and FOLFIRI-bevacizumab (bev, n = 107) was genotyped through the OncoArray, a custom array manufactured by Illumina. Gene expression levels were measured from 102 tumor samples of pts in the cet arm by HTG EdgeSeq Oncology Biomarker Panel. PFS and OS outcomes were investigated for an HLAE genetic polymorphism, rs1264457, where G > A leads to glycine > arginine, where glycine has stronger affinity for NK cell receptor. Results: FOLFIRI/cet and FOLFIRI/bev cohort characteristics: median FU (29.1/26.7mo); PFS (12.8/11.5mo); OS (49.8/31.4mo); RAS WT (64%/62%) and RAS mut (15%/16%). Overexpression of HLAE was associated with poor OS (log2 > 13, 30 vs 34 mo) in cet arm (P < .05). No significant association was observed with PFS. Multivariable analysis showed that HLAErs1264457 carriers with any A allele (n = 65) had better PFS than pts with G/G genotype (n = 18) in RAS WT pts treated with FOLFIRI/cet (12.9 vs 12.3 mo; HR = 2.36; 95%CI = 1.14-4.88; p = 0.021). A non-significant trend of improved OS was seen among carriers of A allele than G/G genotype (56.2 vs 40 mo). These effects were not observed in Ras mut pts. No significance was observed in FOLFIRI/bev overall or FOLFIRI/bev RAS WT pts. Conclusions: Overexpression of HLAE leads to poor OS among pts treated with FOLFIRI/cet. Poor PFS was seen among pts treated with cet who are RAS wt carrying polymorphisms allowing for increased binding to NK cell receptor, which in turn enhances HLAE inhibitory function of NK cell lysis. Addition of mAb against HLAE, which have been shown to restore NK cell mediated cell lysis, needs investigation in this pt population.

The clinical impact of preoperative body composition differs between male and female colorectal cancer patients

AIM

Patient body composition is an important indicator of metabolic status and is associated with cancer progression. Because body composition varies between men and women, we aimed to examine the difference in clinical impact of preoperative body composition according to sex.

METHOD

We used an integrated dataset of 559 colorectal cancer (CRC) patients. The association between preoperative body composition indices [body mass index (BMI), visceral to subcutaneous fat area ratio (VSR) and skeletal muscle index (SMI)] and patient outcome, clinicopathological factors and preoperative inflammation and nutritional status was analysed, comparing men and women.

RESULTS

Preoperative low BMI and low SMI in men was significantly associated with unfavourable overall survival (OS) [BMI: hazard ratio (HR) 2.22, 95% CI 1.28-4.14, P = 0.004; SMI: HR 2.54, 95% CI 1.61-4.07, P < 0.001] and high VSR in women was significantly associated with unfavourable OS (HR 1.79, 95% CI 1.03-3.02, P = 0.040). Additionally, low SMI in men was significantly associated with deeper tumour invasion and greater distant metastasis and high VSR in women was significantly associated with advanced age, right-sided tumour, lower total lymphocyte count and lower albumin levels. Interestingly, low BMI in men was significantly associated with deeper tumour invasion, but also with favourable inflammation and nutritional status (lower C-reactive protein and higher albumin).

CONCLUSION

The clinical impact of preoperative body composition differed between men and women: SMI in men and VSR in women were good prognosticators. Our findings may provide a novel insight for CRC treatment strategies.

Long-term outcomes of colorectal cancer surgery for elderly patients: a propensity score-matched analysis

PURPOSE

To investigate the effect of old age on the perioperative, short-term, and long-term surgical outcomes of elderly patients undergoing curative surgery for colorectal cancer (CRC).

METHODS

The subjects of this retrospective study were 526 patients who underwent curative resections for stage I-III CRC between March 2005 and March 2016. We divided the patients into a young group (< 75 years old, n = 361) and an elderly group (≥ 75 years old, n = 165) and compared the clinicopathological factors and prognoses of the two groups. We performed a propensity score-matched (PSM) analysis with inverse probability of treatment weighting (IPTW) to avoid confounding bias.

RESULTS

The elderly group had more right-sided tumors and more comorbidities than the young group. After PSM, there were 148 patients in each group. Although the elderly group had significantly shorter overall survival than the young group, the two groups did not differ significantly in cancer-specific survival (CSS; P = 0.136) or recurrence rate (RR; P = 0.317). Multivariate analysis with IPTW also revealed no significant difference in CSS (P = 0.171) or RR (P = 0.284) between the young and elderly groups. Our findings were limited by the study's retrospective single-institute conditions, and the inclusion of only patients who underwent radical resections.

CONCLUSION

Primary tumor resection is appropriate for elderly patients with CRC.

Prognostic significance of serum p53 antibody according to KRAS status in metastatic colorectal cancer patients

BACKGROUND

Serum anti-p53 antibody is used clinically as a tumor marker of colorectal cancer. However, its prognostic significance in patients with metastatic colorectal cancer (mCRC) remains unclear. KRAS status may influence the host immune response against tumor progression. In the present study, we investigated the prognostic significance of serum anti-p53 in mCRC patients with wild-type KRAS and mutant KRAS treated with systemic chemotherapy.

METHODS

A retrospective study of 150 mCRC patients in whom serum anti-p53 antibody was measured before first-line chemotherapy was conducted. The patients were divided into two groups, high p53 and low p53, based on their serum anti-p53 antibody levels. Associations between serum anti-p53 level and clinical outcomes were evaluated in conjunction with KRAS status.

RESULTS

There were 97 (64.7%) patients with wild-type KRAS and 53 (35.3%) with mutant KRAS. In an analysis of all patients, there was no significant difference in overall survival (OS) between the high p53 and low p53 groups. In patients with mutant KRAS, those in the high p53 group exhibited significantly longer OS than those in the low p53 group (p = 0.017, log-rank test). In the multivariate analysis, serum p53 antibody level was an independent predictor of OS in mCRC patients (high vs. normal; hazard ratio 0.438, 95% confidence interval 0.178-0.974, p < 0.05).

CONCLUSIONS

Serum anti-p53 antibody level may be an independent predictor of OS in mCRC patients with KRAS mutant tumors.

AMPK variant, a candidate of novel predictor for chemotherapy in metastatic colorectal cancer: A meta-analysis using TRIBE, MAVERICC and FIRE3

AMP-activated protein kinase (AMPK) is a key sensor of energy homeostasis and regulates cell metabolism, proliferation and chemotherapy/radiotherapy sensitivities. This study aimed to explore the relationship between the AMPK pathway-related single nucleotide polymorphisms (SNPs) and clinical outcomes in patients with metastatic colorectal cancer (mCRC). We analyzed a total of 884 patients with mCRC enrolled in three randomized clinical trials (TRIBE, MAVERICC and FIRE-3: where patients were treated with FOLFIRI, mFOLFOX6 or FOLFOXIRI combined with bevacizumab or cetuximab as the first-line chemotherapy). The association between AMPK pathway-related SNPs and clinical outcomes was analyzed across the six treatment cohorts, using a meta-analysis approach. Our meta-analysis showed that AMPK pathway had significant associations with progression-free survival (PFS; p < 0.001) and overall survival (OS; p < 0.001), but not with tumor response (TR; p = 0.220): PRKAA1 rs13361707 was significantly associated with favorable PFS (log HR = -0.219, SE = 0.073, p = 0.003), as well as PRKAA1 rs10074991 (log HR = -0.215, SE = 0.073, p = 0.003), and there were suggestive associations of PRKAG1 rs1138908 with unfavorable OS (log HR = 0.170, SE = 0.083, p = 0.041), and of UBE2O rs3803739 with unfavorable PFS (log HR = 0.137, SE = 0.068, p = 0.042) and OS (log HR = 0.210, SE = 0.077, p = 0.006), although these results were not significant after false discovery rate adjustment. AMPK pathway-related SNPs may be predictors for chemotherapy in mCRC. Upon validation, our findings would provide novel insight for selecting treatment strategies.

Abstract 1342: Polymorphisms in genes involved in mitophagy pathway predict clinical outcome in patients (pts) with metastatic colorectal cancer (mCRC): Data from TRIBE and FIRE3 phase III trials

Background: Mitophagy is the selective degradation of mitochondria by autophagy. Recent studies are suggesting that dysregulation of mitophagy pathway contributes to neoplastic progression and drug resistance in various types of tumors, includes colorectal cancer. We hypothesized genetic variants in mitophagy pathway genes may predict clinical outcome in mCRC pts treated with bevacizumab-based chemotherapy.

Methods: Genomic DNA extracted from blood samples of pts enrolled in two independent randomized phase III trials, TRIBE and FIRE3. 16 SNPs from 4 mitopahgy pathway genes (PINK1, BNIP3, NIX and PARK2), which were selected based on frequency and function, were genotyped by PCR-based direct DNA sequencing. The associations between SNPs and clinical outcomes were analyzed using chi-square test for tumor response, and the Kaplan-Meier curves and Cox regression for PFS and OS.

Results: A total of 451 pts were included in the analysis. TRIBE FOLFIRI/bevacizumab (bev) arm served as discovery cohort (n = 215, median PFS/OS: 9.7/26.2 mo), FIRE3 FOLFIRI/bev arm as validation cohort (n = 107, mPFS/OS: 11.5/31.4 mo). In the discovery cohort, pts carrying the BNIP3 rs4450 C/C variant showed an increased tumor response rate compared to pts with any T allele (65.3% vs 50.5%, p = 0.032); this finding was consistent in overall pts in FIRE3 cohort, pts with BNIP3 rs4550 C/C genotype had increased tumor response rate compared to pts with any T allele (75% vs 53.8%, p = 0.024). Additionally, in the discovery cohort, pts with BNIP3 rs11556626 any C allele showed a longer PFS (12.7 vs 9.5 mo) and OS (49.1 vs 25.6 mo) compared to pts with A/A variant in both univariate (PFS: HR = 0.52; 95%CI 0.34-0.81; p = 0.002) (OS: HR = 0.50; 95%CI 0.31-0.81; p = 0.004) and multivariable analysis (PFS:HR =0.46; 95%CI 0.28-0.76; p=0.002) (OS:HR =0.45; 95%CI 0.27-0.76; p=0.003).

Conclusions: Our results demonstrated for the first time that mitophagy pathway gene BNIP3 polymorphism may have a predictive value in mCRC pts treated with bevacizumab based chemotherapy. This finding supports a possible role of mitophagy BNIP3 genes in contributing to resistance to antiVEGF treatment.

Citation Format: Stephanie Zhang, Joshua Millstein, Shu Cao, Francesca Battaglin, Ryuma Tokunaga, Shivani Soni, Jae Ho Lo, Tricia Ning, Vittorina Zagonel, Chiara Cremolini, Sebastian Stintzing, Fotios Loupakis, Alfredo Falcone, Volker Heinemann, Heinz-Josef Lenz. Polymorphisms in genes involved in mitophagy pathway predict clinical outcome in patients (pts) with metastatic colorectal cancer (mCRC): Data from TRIBE and FIRE3 phase III trials [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1342.

Frequency of BRCA mutation in biliary tract cancer and its correlation with tumor mutational burden (TMB) and microsatellite instability (MSI)

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Background: Biliary tract cancers constitute ~3% of cancers worldwide with incidence increasing, especially for intrahepatic cholangiocarcinoma (IHC). The prognosis of these tumors remains dismal and novel treatment strategies are needed to improve overall survival. BRCA mutations occur in biliary tract cancers but their frequency in distinct sites of biliary tract cancer is unknown. Moreover, no data are available correlating BRCA mutation with immunogenic markers such as TMB, MSI, or PD-L1 expression. Methods: Tumor samples from 1288 primary biliary tract cancers, comprising IHC (n = 746), extrahepatic cholangiocarcinoma (EHC) (n = 189), gallbladder (GBC) (n=353) were profiled at Caris Life Sciences, Phoenix, AZ. Testing included NextGen SEQ (MiSeq on 47 genes, NextSeq on 592 genes) and PD-L1 IHC (SP142). TMB was calculated based on somatic nonsynonymous missense mutations, and MSI was evaluated by NGS of known MSI loci. Results: BRCA mutations were detected in 3.6% (N = 46) of samples ( BRCA1 0.6%, BRCA2 3%), no differences were seen based on the site of the tumor. In GBC and IHC BRCA2 mutations (4.0% and 2.7%) were more frequent than BRCA1 (0.3% and 0.4, p < 0.05) while in EHC, similar frequency was observed ( BRCA1: 2.1%; BRCA2: 2.6%). There was no significant association with gender or age. In BRCA-mutant biliary tract cancer the most frequently mutated genes were TP53 (55.6%), ARID1A (52.2%) and KRAS (26.1%), KMT2D/C (20%, 13%) and CDKN2A(13%). Overall, BRCA mutations were associated with a higher rate of MSI-H (19.5% vs 1.7%, p = 0.001) and higher TMB in both MSI-H and MSS tumors (p<0.05). When investigated separately, BRCA association with elevated TMB was seen in IHC and EHC, but not in GBC. No correlation was seen with PD-L1 expression. TP53, KMT2D/C, RB1, PTEN, KDM6A mutations and FGFR1 amplifications were significantly higher in BRCA mutated tumors (p < 0.05). Conclusions: BRCA mutations are found in a significant subgroup of biliary tract tumors and are associated with an immunogenic tumor profile. These data provide rationale for trials testing PARP inhibitors in combination with immunotherapy and targeted therapies in patients with BRCA-mutant biliary tract cancers that are MSS.

BRCA1 genetic variant to predict survival in metastatic colorectal cancer (mCRC) patients (pts) treated with FOLFIRI/bevacizumab (bev): Results from phase III TRIBE and FIRE-3 trials

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Background: BRCA muts in CRC are associated with a higher tumor mutation burden irrespective of microsatellite instability, which highlights the possibility of using PARP-inhibitors(i) in CRC in the future. Early phase studies have shown that combination of PARP-i with oxaliplatin or irinotecan enhances tumor lysis in CRC. In this study, we investigated the influence of mutations in the Homologous Repair Pathway genes on survival outcomes among mCRC pts treated with oxaliplatin or irinotecan-based regimens. Methods: The impact of selected SNPs within 4 genes (BRCA1, BRCA2, RAD51, BARD1) on OS/PFS was analyzed through the OncoArray, a custom array manufactured by Illumina, on genomic DNA from blood samples of 431 pts enrolled in 2 randomized trials. TRIBE FOLFIRI/bev arm (n = 215, mPFS/OS: 9.7/26.2 mo) served as discovery cohort, FIRE-3 FOLFIRI/bev arm (n = 107, mPFS/OS: 11.5/31.4 mo) as validation and TRIBE FOLFOX/bev arm (n = 109, mPFS/OS: 10.8/26 mo) as control. Results: Significant associations were found among carriers of BRCA1 rs8176318 SNP, where C > A base change is known to reduce BRCA1 expression among CRC cells. In the discovery cohort, pts with A/A had shorter OS (22.4 vs 27.3 mo, P = .009) and PFS (7.5 vs 10.5 mo, P = .0006) compared to carriers of any C allele in both univariate and multivariate analysis. Same results were observed in pts with left-sided CRCs (PFS-7.5 vs 11 mo, P = .005; OS- 25.6 vs 32.3, P = .034) and among males (PFS- 7.5 vs 10.3 mo, P = .008; OS- 25.7 vs 31.3 mo, P = .008) in both uni and multivariate analysis. These results were also seen in the validation cohort: A/A carriers in left-sided CRCs had poor OS (26.1 vs 36.0 mo, P = .027) and PFS (9.5 vs 11.7 mo, P = .002. Males with A/A genotype also had poor OS (24.7 vs 32.5 mo, P = .028) and PFS 96.9 vs 12.2 mo; P = .0002). In the control cohort, A/A genotype carriers had poor tumor response in overall (P = .011) and left-sided disease (P = .034). These outcomes were independent of KRAS mutation status. No significant relationship was observed among females with mCRC. Conclusions: This is the first study to report that BRCA1 mut influence survival outcomes among mCRC pts, particularly among males and those with left-sided disease. Prospective trials are warranted to assess the utility of routine BRCA mut testing and the role of PARP-i in improving survival outcomes in this pt population.

Gene mutations of SWI/SNF complex and molecular profile in colorectal cancer

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Background: The SWI/SNF complex includes proteins produced by 29 genes that regulate chromatin structure remodeling through effects upon transcription, replication, and repair. Understanding how SWI/SNF gene mutations interact to affect cancer progression could lead to new treatment strategies. Methods: We analyzed 7,370 colorectal cancer (CRC) samples with immunohistochemical stains (IHC) and Next-Generation Sequencing (NGS) using a 592-gene panel to examine the association between gene mutations of the SWI/SNF complex ( ARID1A, ARID2, PBRM1, SMARCA4, SMARCB1, SMARCE1, BCL11A, BCL11B, BCL7A, SS18, and SS18L1) and molecular features. Results: The overall mutation rate of the SWI/SNF complex genes was 11.3% ( ARID1A: 7.7% , ARID2: 1.7% , SMARCA4: 1.3% , PBRM1: 1.2% , BCL11A: 1.0% , SMARCB1: 0.5% , BCL11B: 0.5% , SMARCE1: 0.3% , SS18: 0.3% , BCL7A: 0.1% , SS18L1: 0.1%). When compared to tumors with SWI/SNF wild-type genes, those tumors with SWI/SNF gene mutations showed significantly higher rates of microsatellite instability (MSI)-high (40.9% vs 2.4%, P < 0.001), tumor mutational burden (TMB)-high (>= 10mut/MB) (56.8% vs 21.6%, P < 0.001) and PD-L1 positivity (17.9% vs 5.5%, P < 0.001). Tumors with each gene mutant also had strong association with the immune profile (MSI-high, TMB-high, and PD-L1 positivity) (Table). Furthermore, even SWI/SNF gene mutant samples with microsatellite stable status were significantly associated with TMB-high (28.2%, P < 0.001) and PD-L1 positivity (10.0%, P < 0.001). Conclusions: Gene mutations of the SWI/SNF complex exhibit findings that suggest that this subgroup of CRCs may have a higher likelihood of response to PD-1 and PD-L1 targeting monoclonal antibodies. If validated in other data sets, these findings can be used to justify clinical trials with eligibility based upon the presence of mutations within the SWI/SNF complex. [Table: see text]

Association of genetic variations within the T-cell costimulatory LIGHT gene with outcome in stage II and III colon cancer

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Background: T-cell activation plays a key role in maintaining an effective host immunity and antitumor control. Targeting costimulatory immune checkpoint proteins can lead to increased antitumor immunity. We hypothesize, that variations in genes encoding for T-cell activation molecules may predict outcome in stage II and III colon cancer patients. Methods: The impact of 4 functional single nucleotide polymorphisms (SNPs) within the LIGHT, ICOS, CD80 and GITR genes on time to recurrence and overall survival was evaluated in 209 patients with stage II and III colon cancer. Genomic DNA was extracted from formalin-fixed paraffin embedded tissue and the SNPs were analyzed by PCR-based direct sequencing. Results: Baseline characteristics were as follows: median age = 70y (19-91); female/male ratio = 41.6% / 58.4%; 111 patients had stage II, and 98 stage III colon cancer. The LIGHT rs3760746 SNP showed significant association with recurrence rate in the overall population. Patients harboring any G allele had a lower 3-years recurrence rate compared to those with a A/A genotype (16% vs 30%) in both univariate (HR 0.53, 95% Confidence intervall (CI) 0.29-0.96, p = 0.033) and multivariate analyses (HR 0.52, 95% CI 0.29-0.95, p = 0.034). This trend was most evident among patients with stage III colon cancer. Here again, G allele carriers had both a lower 3-years recurrence and a longer 5-years overall survival rate compared to those having a A/A genotype (21% vs 40% and 77% vs 43%) in both univariate (HR 0.42, 95% CI 0.19-0.90, p = 0.021 and HR 0.51, 95% CI 0.25-1.03, p = 0.046) and multivariate analyses (HR 0.43, 95% CI 0.20-0.93, p = 0.033 and HR 0.30, 95% CI 0.14-0.65, p = 0.002). Conclusions: Our results provide the first evidence that polymorphisms within the T-cell costimulatory LIGHT gene might serve as prognostic markers in patients with stage II and III colon cancer. Targeting LIGHT might be a promising approach to further optimize treatment options and to improve outcome of colon cancer patients in the adjuvant setting.

Molecular differences between lymph nodes (LNs) and distant metastases (mets) in colorectal cancer (CRC)

3130

Background: LNs mets are thought to occur before distant mets. However, lymphatic and distant mets arise from independent subclones of the primary tumor, suggesting that LNs are not essential intermediaries for distant mets. We aimed to comprehensively characterize the molecular profile of LN mets and to explore the differences between LN vs distant mets and primary tumors. Methods: Tumor samples from primary CRCs, LNs, and distant mets were analyzed using NGS (MiSeq on 47 genes, NextSeq on 592 genes), immunohistochemistry. Tumor mutational burden (TMB) was calculated based on somatic nonsynonymous missense mutations, and microsatellite instability (MSI) was evaluated by NGS of known MSI loci. Results: In total, 11871 tumors samples were examined, comprising primaries (N = 5862), distant (N = 5605) and LNs mets (N = 404). The most frequently mutated genes in LNs were TP53 (72%), APC (61%), KRAS (39%), ARID1A (20%), and PIK3CA (12%). LNs showed a higher mean TMB (13 mut/MB) vs distant mets (9, P < .0001). TMB-high (17mut/MB) was more frequent in primaries and LNs vs distant mets (9.5% and 8.8% vs 4.2%, P < .001 and P = .001, respectively), as well as MSI-H (8.8% and 6.9% vs 3.7%, P < .001 and P = .017, respectively). TMB-high is significantly higher in LNs vs distant mets and primaries (P < .0001), independent of MSI-H status. Analyzing distant mets by location, LNs showed higher TMB compared to lung, liver and peritoneum mets (P < .0001). Overall, LNs showed significantly different rates of mutations in APC, KRAS, PI3KCA, KDM6A, and BRIP1 (P < .01 for all comparisons) vs primaries; while presenting a distinct molecular profile compared to distant mets ( TP53 72 vs 67%; KRAS 39 vs 50%; RNF43 7 vs 4%; ATM 5 vs 3%; KDM6A 4 vs 1%; BRCA2 4 vs 2%; MSH6 3 vs 2%; PTCH1 4 vs 1%; BRCA1 2 vs 1%; GNAS 2 vs 5%; P < .05 for all comparisons). Our cohort of 30 paired samples confirmed the molecular heterogeneity between primaries, LNs, and distant mets. Conclusions: This is the largest study to investigate the molecular differences between LNs mets, distant mets and primary tumors in CRC patients. Our data support the hypothesis that lymphatic and distants mets harbor different mutation profiles which suggests that they may arise from distinct subclones.

Polymorphisms in the dopamine (DA) signaling to predict outcome in patients (pts) with metastatic colorectal cancer (mCRC): Data from TRIBE, MAVERICC, and FIRE-3 phase III trials

3048

Background: Strong evidence supports the critical role of the gut-brain axis in modulating gastrointestinal function and homeostasis. Available data suggest an involvement of the dopaminergic pathway in CRC dynamics. DA could inhibit proliferation and migration of tumor endothelial cells and enhanced 5-fluorouracil efficacy in CRC preclinical models. Hence, we hypothesized that genetic variants in DA signaling may predict treatment outcomes in mCRC pts. Methods: The impact on outcome of 22 selected single nucleotide polymorphisms (SNPs) in 9 genes of the DA signaling pathway ( DRD1, DRD2, DRD3, DRD4, DRD5, TAAR1, SLC6A3, SLC18A2, PPP1R1B) was analyzed on a total of 884 pts enrolled in three independent randomized first-line trials: TRIBE (n = 324), MAVERICC (n = 324), and FIRE-3 (n = 236). Genomic DNA from blood samples of pts was genotyped through the OncoArray, a custom array manufactured by Illumina. A meta-analysis approach using the METASOFT software was used to quantify SNPs prognostic effects and heterogeneities across treatment arms. P values were adjusted for multiple testing using the false discovery rate (FDR) method. Results: Overall, DRD3 rs3732790, rs9817063 and rs2134655 showed a significant nominal p value ( P) in association with tumor response (TR) across trials ( P= 0.032, P= 0.021, P= 0.027, respectively). TAAR1 rs8192620 showed an association with both progression free survival (PFS) ( P= 0.01) and overall survival (OS) ( P= 0.033), similar to DA transporter SLC6A3 rs6347 ( P= 0.016 and P= 0.002, respectively). SLC6A3 rs6347 association with OS remained significant after FDR ( PFDR= 0.045). Subgroup analyses showed a significant association with PFS for DRD1 rs267410 and SLC6A3 rs2652510 in females ( PFDR= 0.056), and between SLC6A3 rs6347 and OS ( PFDR= 0.041) and SLC6A3 rs6876890 and TR ( PFDR= 0.05) in KRAS wild type. Conclusions: Our results suggest that SNPs in DA signaling may have a prognostic value in mCRC pts receiving first-line treatment. Upon validation, these findings may provide novel insight on the role of DA signaling in CRC and possibly contribute to open novel therapeutic perspectives.

Association of BRCA-mutant pancreatic cancer with high tumor mutational burden (TMB) and higher PD-L1 expression

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Background: In the U.S. 56,000 Americans are expected to be diagnosed with pancreatic cancer in 2019. Prognosis in pancreatic cancer is poor. Therefore, new treatment strategies are urgently needed to improve survival. BRCA1 and BRCA2 mutations have been described to be the most common genetic mutations involved in familial pancreatic cancer. The optimal treatment regimen to use in BRCA-mutant pancreatic cancer has still to be established. Moreover, no data are available on association of BRCA mutation with immune-associated markerssuch as tumor mutational burden (TMB), microsatellite instability (MSI) or PD-L1 expression. Methods: Tumor samples of 2824 patients with pancreatic ductal adenocarcinoma were analyzed for BRCA mutation by NGS and for other genes (MiSeq on 47 genes, NextSeq on 592 genes) at Caris Life Sciences, Phoenix, AZ. TMB was calculated based on somatic nonsynonymous missense mutations, and MSI was evaluated by NGS of known MSI loci. PD-L1 expression was evaluated using immunohistochemistry. Results: In 4.4% (N = 124) of all pancreatic adenocarcinoma samples BRCA mutations were detected. BRCA2 mutations were more common: 3.1% (N = 89) vs 1.1% BRCA1 mutations (N = 35). BRCA mutations were associated with younger age ( BRCA1: 61 yrs for mutated vs. 64 for wild-type, p = 0.07; BRCA2: 61 yrs vs. 64, p = 0.002; both: p < 0.001). BRCA mutations were associated with higher MSI-H frequency (4.8% vs. 1.2%, p = 0.002), elevated PD-L1 expression (22% vs. 11%, p < 0.001) and higher TMB (mean 8.7 mut/MB vs. 6.5, p < 0.001); the differences remain significant in MSS tumors (p < 0.05). BRCA-mutant pancreatic carcinomas showed a significantly lower mutation frequencies in TP53 (59% vs 73%, p = 0.001), CKDN2A (13% vs 25%, p = 0.006), but higher frequencies in APC (6.5% vs 2.2%), KMT2A (1.9% vs 0.2%), AMER1 (1.9 vs 0.5%) and SETD2 (3.7% vs 0.4%) mutations (p < 0.05 for all comparisons). Conclusions: BRCA mutations are found in a significant subgroup of pancreatic ductal adenocarcinoma and these carcinomas are associated with an immunogenic tumor profile. These data suggest evaluating PARP inhibitors in combination with immunotherapy in patients with BRCA-mutant pancreatic adenocarcinoma especially in tumors that are MSS.