Novel insights into tumorigenesis revealed by molecular analysis of Lynch syndrome cases with multiple colorectal tumors.

Background: Lynch syndrome (LS) is an autosomal dominant multi-organ cancer syndrome with a high lifetime risk of cancer. The number of cumulative colorectal adenomas in LS does not generally exceed ten, and removal of adenomas via routine screening minimizes the cancer burden. However, abnormal phenotypes may mislead initial diagnosis and subsequently cause suboptimal treatment. Aim: Currently, there is no standard guide for the care of multiple colorectal adenomas in LS individuals. We aimed to shed insight into the molecular features and reasons for multiplicity of adenomas in LS patients. Methods: We applied whole exome sequencing on nine adenomas (ten samples) and three assumed primary carcinomas (five samples) of an LS patient developing the tumors during a 21-year follow-up period. We compared the findings to the tumor profiles of two additional LS cases ascertained through colorectal tumor multiplicity, as well as to ten adenomas and 15 carcinomas from 23 unrelated LS patients with no elevated adenoma burden from the same population. As LS associated cancers can arise via several molecular pathways, we also profiled the tumors for CpG Island Methylator Phenotype (CIMP), and LINE-1 methylation. Results: All tumors were microsatellite unstable (MSI), and MSI was present in several samples derived from normal mucosa as well. Interestingly, frequent frameshift variants in RNF43 were shared among substantial number of the tumors of our primary case and the tumors of LS cases with multiple tumors but almost absent in our control LS cases. The RNF43 variants were completely absent in the normal tissue, indicating tumor-associated mutational hotspots. The RNF43 status correlated with the mutational signature SBS96. Contrary to LS tumors from the reference set with no elevated colorectal tumor burden, the somatic variants occurred significantly more frequently at C>T in the CpG context, irrespective of CIMP or LINE-1 status, potentially indicating other, yet unknown methylation-related mechanisms. There were no signs of somatic mosaicism affecting the MMR genes. Somatic variants in APC and CTNNB1 were unique to each tumor. Conclusion: Frequent somatic RNF43 hot spot variants combined with SBS96 signature and increased tendency to DNA methylation may contribute to tumor multiplicity in LS.

Postoperative Delayed Emptying after Total, Subtotal, or Distal Gastrectomy for Gastric Cancer - a Population-based Study.

BACKGROUND: To examine the rate of delayed emptying and other 90-day postoperative complications after total, subtotal, and distal gastrectomy for gastric adenocarcinoma in a population-based setting. METHODS: This study included all patients undergoing total, subtotal, or distal gastrectomy for gastric cancer in Finland in 2005-2016, with follow-up until December 31, 2019. Logistic regression provided odds ratios with 95% confidence intervals of 90-day mortality. Results were adjusted for age, sex, year of surgery, comorbidities, pathological stage, surgical approach, and neoadjuvant therapy. RESULTS: A total of 2,058 patients underwent total (n=1,227), subtotal (n=450), or distal (n=381) gastrectomy. The rate of delayed emptying was 1.7% vs. 1.3% vs. 2.1% in the whole cohort and 1.6% vs. 1.8% vs. 3.5% in the subgroup analysis of R0 resections, respectively. Resection type was not associated to the risk of delayed emptying. Subtotal gastrectomy was associated with lower risk of major complications and re-operations and distal gastrectomy was associated with lower risk of anastomotic leak. CONCLUSIONS: The extent of resection did not affect delayed emptying while less postoperative complications were seen after subtotal or distal gastrectomy compared to total gastrectomy.

Stapled vs handsewn anastomosis and anastomotic leaks in gastric cancer surgery-a population-based nationwide study in Finland.

BACKGROUND: There is a lack of evidence regarding anastomotic technique and postoperative complications in gastric cancer surgery. This study aimed to evaluate whether there are differences between stapled and handsewn anastomosis and anastomotic leaks. METHODS: This was a population-based, retrospective, nationwide cohort study in Finland using the Finnish National Esophago-Gastric Cancer Cohort. Patients undergoing gastrectomy with available postoperative complication data were included. Logistic regression analysis was used to calculate the odds ratios with 95% CIs, adjusted for calendar period of surgery, age at surgery, sex, comorbidity, tumor stage, neoadjuvant therapy, minimally invasive surgery, type of gastrectomy, radical resection, and type of anastomosis. RESULTS: Of the 2164 patients, 472 of all patients (21.8%) had handsewn anastomosis and 1692 of all patients (78.2%) had stapled anastomosis. In the unadjusted analysis, anastomotic leaks were significantly lower in the handsewn group (hazard ratio [HR], 0.42; 95% CI, 0.22-0.79) than the stapled group, but after adjustment for known prognostic factors, this association was no longer significant (HR, 0.57; 95% CI, 0.27-1.21). In the analysis stratified by gastrectomy type (distal or total), no differences in anastomotic leaks were observed between anastomotic techniques. CONCLUSION: In this population-based nationwide study, anastomotic technique (stapled or handsewn) was not associated with anastomotic leaks in any, distal or total, gastrectomy.

Impact of Primary Tumor Location on Demographics, Resectability, Outcomes, and Quality of Life in Finnish Metastatic Colorectal Cancer Patients (Subgroup Analysis of the RAXO Study).

The primary tumor location (PTL) is associated with the phenotype, metastatic sites, mutations, and outcomes of metastatic colorectal cancer (mCRC) patients, but this has mostly been studied according to sidedness (right vs. left sided). We studied right colon vs. left colon vs. rectal PTL in a real-life study population (n = 1080). Health-related quality of life (HRQoL) was assessed multi-cross-sectionally with QLQ-C30, QLQ-CR29, EQ-5D, and 15D. A chi-square, Kaplan-Meier, and Cox regression were used to compare the groups. The PTL was in the right colon in 310 patients (29%), the left colon in 396 patients (37%), and the rectum in 375 patients (35%). The PTL was associated with distinct differences in metastatic sites during the disease trajectory. The resectability, conversion, and resection rates were lowest in the right colon, followed by the rectum, and were highest in the left colon. Overall survival was shortest for right colon compared with left colon or rectal PTL (median 21 vs. 35 vs. 36 months), with the same trends after metastasectomy or systemic therapy only. PTL also remained statistically significant in a multivariable model. The distribution of symptoms varied according to PTL, especially between the right colon (with general symptoms of metastases) and rectal PTL (with sexual- and bowel-related symptoms). mCRC, according to PTL, behaves differently regarding metastatic sites, resectability of the metastases, outcomes of treatment, and HRQoL.

GNAS mutation inhibits growth and induces phosphodiesterase 4D expression in colorectal cancer cell lines.

Approximately 5% of colorectal cancers (CRCs) have a gain-of-function mutation in the GNAS gene, which leads to the activation of cAMP-dependent signaling pathways and associates with poor prognosis. We investigated the effect of an activating GNAS mutation in CRC cell lines on gene expression and cell proliferation in vitro, and tumor growth in vivo. GNAS-mutated (GNASmt) HCT116 cells showed stimulated synthesis of cAMP as compared to parental (Par) cells. The most upregulated gene in the GNASmt cells was cAMP-hydrolyzing phosphodiesterase 4D (PDE4D) as detected by RNA sequencing. To further validate our finding, we analyzed PDE4D expression in a set of human CRC tumors (n = 35) and demonstrated overexpression in GNAS mutant CRC tumors as compared to GNAS wild-type tumors. The GNASmt HCT116 cells proliferated more slowly than the Par cells. PDE4 inhibitor Ro 20-1724 and PDE4D subtype selective inhibitor GEBR-7b further suppressed the proliferation of GNASmt cells without an effect on Par cells. The growth inhibitory effect of these inhibitors was also seen in the intrinsically GNAS-mutated SK-CO-1 CRC cell line having high levels of cAMP synthesis and PDE4D expression. In vivo, GNASmt HCT116 cells formed smaller tumors than the Par cells in nude mice. In conclusion, our findings demonstrate that GNAS mutation results in the growth suppression of CRC cells. Moreover, the GNAS mutation-induced overexpression of PDE4D provides a potential avenue to impede the proliferation of CRC cells through the use of PDE4 inhibitors.

Postoperative Complications After Neoadjuvant Chemotherapy Versus Upfront Surgery in Gastric Adenocarcinoma: A Population-Based Nationwide Study in Finland.

BACKGROUND: To date, no large population-based studies have compared complications and short-term outcomes between neoadjuvant chemotherapy and upfront surgery in gastric cancer. More nationwide studies with standardized reporting on complications are needed to enable international comparison between studies. This study aimed to compare postoperative complications between neoadjuvant therapy and upfront surgery after gastrectomy for gastric adenocarcinoma in a population-based setting. METHODS: This population-based study based on the Finnish National Esophago-Gastric Cancer Cohort included all patients 18 years of age or older undergoing gastrectomy for gastric adenocarcinoma in Finland during 2005-2016. Logistic regression provided odds ratios (ORs) with 95% confidence intervals (CIs), both crude and adjusted for key confounders. Different types of complications were graded based on the Esophagectomy Complications Consensus Group definitions, and major complications were assessed by the Clavien-Dindo scale. RESULTS: This study analyzed 769 patients. Neoadjuvant chemotherapy did not increase major postoperative complications after gastrectomy for gastric cancer compared with upfront surgery (OR, 1.12; 95% CI 0.81-1.56). Furthermore, it did not increase pneumonia, anastomotic complications, wound complications, or other complications. CONCLUSIONS: Neoadjuvant therapy is not associated with increased postoperative complications, reoperations, or short-term mortality compared with upfront surgery in gastric adenocarcinoma.

Atypical (non-V600E) BRAF mutations in metastatic colorectal cancer in population and real-world cohorts.

BRAF-V600E mutation (mt) is a strong negative prognostic and predictive biomarker in metastatic colorectal cancer (mCRC). Non-V600Emt, designated atypical BRAFmt (aBRAFmt) are rare, and little is known about their frequency, co-mutations and prognostic and predictive role. These were compared between mutational groups of mCRC patients collected from three Nordic population-based or real-world cohorts. Pathology of aBRAFmt was studied. The study included 1449 mCRC patients with 51 (3%) aBRAFmt, 182 (13%) BRAF-V600Emt, 456 (31%) RAS&BRAF wild-type (wt) and 760 (52%) RASmt tumours. aBRAFmt were seen in 2% of real-world and 4% of population-based cohorts. Twenty-six different aBRAFmt were detected, 11 (22%) class 2 (serrated adenocarcinoma in 2/9 tested), 32 (64%) class 3 (serrated in 15/25) and 4 (8%) unclassified. aBRAFmt patients were predominantly male, had more rectal primaries, less peritoneal metastases, deficient mismatch repair in one (2%), and better survival after metastasectomy (89% 5-year overall survival [OS]-rate) compared with BRAF-V600Emt. aBRAFmt and BRAF-V600Emt had poorer performance status and received fewer treatment lines than RAS&BRAFwt and RASmt. OS among aBRAFmt (median 14.4 months) was longer than for BRAF-V600Emt (11.2 months), but shorter than for RAS&BRAFwt (30.5 months) and RASmt (23.4 months). Addition of bevacizumab trended for better OS for the aBRAFmt. Nine patients with aBRAFmt received cetuximab/panitumumab without response. aBRAFmt represents a distinct subgroup differing from other RAS/BRAF groups, with serrated adenocarcinoma in only half. OS for patients with aBRAFmt tumours was slightly better than for BRAF-V600Emt, but worse than for RASmt and RAS&BRAFwt. aBRAFmt should not be a contraindication for metastasectomy.

Population-based nationwide incidence of complications after gastrectomy for gastric adenocarcinoma in Finland.

BACKGROUND: The incidence of postoperative complications after gastrectomy for gastric cancer is not well known. More population-based studies using established complication classifications are needed for international comparison. The aim of this study was to evaluate the population-based incidence of postoperative complications after gastrectomy for gastric cancer. METHODS: This population-based study based on the Finnish National Esophago-Gastric Cancer Cohort included all patients at least 18 years of age undergoing gastrectomy for gastric adenocarcinoma in Finland during 2005-2016. The occurrence of complications 30 and 90 days after surgery was graded based on the Esophagectomy Complications Consensus Group definitions and the severity of complications was assessed using the Clavien-Dindo scale. RESULTS: This study included a total of 2196 patients. Postoperative complications occurred in 906 (41.3 per cent) of patients during 30 days after surgery and in 946 (43.1 per cent) during 90 days after surgery. Clavien-Dindo grade III or higher complications occurred in 375 (17.1 per cent) of patients. The most common complications 90 days after surgery by Esophagectomy Complications Consensus Group upper-level categories were gastrointestinal (n = 438; 19.9 per cent), including anastomotic leak, infectious (n = 377; 17.2 per cent) and pulmonary (n = 335; 15.3 per cent) complications. Postoperative mortality rate was occurred in 72 (3.3 per cent) patients within 30 days and in 161 (7.3 per cent) patients within 90 days after surgery. The median duration of postoperative hospital stay was 9 days (interquartile range 4-14). CONCLUSIONS: Postoperative complications are common across all types of gastrectomy and the majority occur during the first 30 postoperative days. This study informs the patients and caregivers of the expected outcomes of gastrectomy.

N-glycosylation in non-invasive and invasive intraductal papillary mucinous neoplasm.

Intraductal papillary mucinous neoplasms (IPMNs), often found incidentally, are potentially malignant cystic tumors of the pancreas. Due to the precancerous nature, IPMNs lacking malignant features should be kept on surveillance. The follow-up relies on magnetic resonance imaging, which has a limited accuracy to define the high-risk patients. New diagnostic methods are thus needed to recognize IPMNs with malignant potential. Here, aberrantly expressed glycans constitute a promising new area of research. We compared the N-glycan profiles of non-invasive IPMN tissues (n = 10) and invasive IPMN tissues (n = 10) to those of non-neoplastic pancreatic controls (n = 5) by matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry. Both IPMN subgroups showed increased abundance of neutral composition H4N4 and decrease in H3N5F1, increase in sialylation, and decrease in sulfation, as compared to the controls. Furthermore, invasive IPMN showed an increase in terminal N-acetylhexosamine containing structure H4N5, and increase in acidic complex-type glycans, but decrease in their complex fucosylation and sulfation, as compared to the controls. In conclusion, the N-glycan profiles differed between healthy pancreatic tissue and non-invasive and invasive IPMNs. The unique glycans expressed in invasive IPMNs may offer interesting new options for diagnostics.

N-Glycomic Profiling of Microsatellite Unstable Colorectal Cancer.

Aberrant glycosylation affects cancer progression and immune evasion. Approximately 15% of colorectal cancers (CRCs) demonstrate microsatellite instability (MSI) and display major differences in outcomes and therapeutic responses, as compared to corresponding microsatellite stable (MSS) tumors. We compared the N-glycan profiles of stage II and IV MSI CRC tumors, further subdivided into BRAFV600E wild-type and mutated subgroups (n = 10 in each subgroup), with each other and with those of paired non-neoplastic mucosal samples using mass spectrometry. Further, the N-glycans of BRAFV600E wild-type stage II MSI tumors were compared to corresponding MSS tumors (n = 9). Multiple differences in N-glycan profiles were identified between the MSI CRCs and control tissues, as well as between the stage II MSI and MSS samples. The MSI CRC tumors showed a lower relative abundance of high-mannose N-glycans than did the control tissues or the MSS CRCs. Among MSI CRC subgroups, acidic N-glycans showed tumor stage and BRAF mutation status-dependent variation. Specifically, the large, sulfated/phosphorylated, and putative terminal N-acetylhexosamine-containing acidic N-glycans differed between the MSI CRC subgroups, showing opposite changes in stages II and IV, when comparing BRAF mutated and wild-type tumors. Our results show that molecular subgroups of CRC exhibit characteristic glycan profiles that may explain certain carcinogenic properties of MSI tumors.

Efficacy and Safety of Glycosphingolipid SSEA-4 Targeting CAR-T Cells in an Ovarian Carcinoma Model.

Chimeric antigen receptor (CAR) T-cell immunotherapies for solid tumors face critical challenges such as heterogeneous antigen expression. We characterized stage-specific embryonic antigen-4 (SSEA-4) cell-surface glycolipid as a target for CAR T-cell therapy. SSEA-4 is mainly expressed during embryogenesis but is also found in several cancer types making it an attractive tumor-associated antigen. Anti-SSEA-4 CAR-T cells were generated and assessed preclinically in vitro and in vivo for antitumor response and safety. SSEA-4 CAR-T cells effectively eliminated SSEA-4-positive cells in all the tested cancer cell lines, whereas SSEA-4-negative cells lines were not targeted. In vivo efficacy and safety studies using NSG mice and the high-grade serous ovarian cancer cell line OVCAR4 demonstrated a remarkable and specific antitumor response at all the CAR T-cell doses used. At high T-cell doses, CAR T cell-treated mice showed signs of health deterioration after a follow-up period. However, the severity of toxicity was reduced with a delayed onset when lower CAR T-cell doses were used. Our data demonstrate the efficacy of anti-SSEA-4 CAR T-cell therapy; however, safety strategies, such as dose-limiting and/or equipping CAR-T cells with combinatorial antigen recognition should be implemented for its potential clinical translation.

Preoperative Esophageal Stenting and 5-Year Survival in Patients Undergoing Esophagectomy for Esophageal Cancer: a Population-Based Nationwide Study from Finland.

BACKGROUND: Preoperative esophageal stenting is proposed to have a negative effect on outcomes. The aim was to compare a 5-year survival in patients undergoing esophagectomy for esophageal cancer with and without preoperative esophageal stent in a population-based nationwide cohort from Finland. The secondary outcome was 90-day mortality. METHODS: This study included curatively intended esophagectomies for esophageal cancer in Finland between 1999 and 2016, with follow-up until December 31, 2019. Cox proportional hazards models provided hazard ratios (HRs) with 95% confidence intervals (CIs) of overall 5-year and 90-day mortality. Model 1 was adjusted for age, sex, year of the surgery, comorbidities, histology, pathological stage, and neoadjuvant therapy. Model 2 included also albumin level and BMI. RESULT: Of 1064 patients, a total of 134 patients underwent preoperative stenting and 930 did not. In both adjusted models 1 and 2, higher 5-year mortality was seen in patients with preoperative stent with HRs of 1.29 (95% CI 1.00-1.65) and 1.25 (95% CI 0.97-1.62), respectively, compared to no stenting. The adjusted HR of 90-day mortality was 2.49 (95% CI 1.27-4.87) in model 1 and 2.49 (95% CI 1.25-4.99) in model 2. When including only neoadjuvant-treated patients, those with preoperative stent had a 5-year survival of 39.2% compared to 46.4% without stent (adjusted HR 1.34, 95% CI 1.00-1.80), and a 90-day mortality rate of 8.5% and 2.5% (adjusted HR 3.99, 95% CI 1.51-10.50). DISCUSSION: This nationwide study reports worse 5-year and 90-day outcomes in patients with preoperative esophageal stent. Since residual confounding remains possible, observed difference could be only an association rather than the cause.

Correlations between Molecular Alterations, Histopathological Characteristics, and Poor Prognosis in Esophageal Adenocarcinoma.

Esophageal adenocarcinoma (EAC) is a severe malignancy with increasing incidence, poorly understood pathogenesis, and low survival rates. We sequenced 164 EAC samples of naïve patients (without chemo-radiotherapy) with high coverage using next-generation sequencing technologies. A total of 337 variants were identified across the whole cohort, with TP53 as the most frequently altered gene (67.27%). Missense mutations in TP53 correlated with worse cancer-specific survival (log-rank p = 0.001). In seven cases, we found disruptive mutations in HNF1alpha associated with other gene alterations. Moreover, we detected gene fusions through massive parallel sequencing of RNA, indicating that it is not a rare event in EAC. In conclusion, we report that a specific type of TP53 mutation (missense changes) negatively affected cancer-specific survival in EAC. HNF1alpha was identified as a new EAC-mutated gene.

Diagnostic performance of Idylla MSI test in colorectal cancer biopsies.

Universal testing for microsatellite instability (MSI) is recommended in colorectal cancer (CRC) to screen for Lynch syndrome and to guide optimal treatment and follow-up of the patients. Especially in neoadjuvant setting, where immuno-oncological treatments have recently shown excellent responses, identification of MSI status at biopsy is a prerequisite. Idylla MSI test offers a rapid and automated test to assess MSI-status from formalin-fixed paraffin-embedded tumor tissue sections. In this study, we compared the performance of the Idylla MSI test to mismatch repair (MMR) protein immunohistochemistry (IHC) using 117 CRC biopsies with previously known deficient MMR status. The concordance between Idylla and IHC was 99.0% (95/96) for biopsies with the recommended ≥ 20% tumor cell content. Further, 85.7% (18/21) of suboptimal CRC biopsy specimens (tumor cell content 5-15%) were diagnosed as MSI. Overall, we identified four discrepant cases of which three had tumor cell content less than 20%, explaining the discordant result. Our study shows that the Idylla MSI test offers a competent tool for MSI screening in CRC biopsy specimens.

Health-related quality of life and anxiety levels among patients under surveillance for intraductal papillary mucinous neoplasm.

BACKGROUND: Because of the premalignant nature of intraductal papillary mucinous neoplasms (IPMNs), patients should undergo surveillance as long as they remain fit for surgery. This surveillance, with imaging and laboratory tests every 6 to 12 months, is expensive and may psychologically burden patients. This study aimed to determine the effects of IPMN surveillance on patients´ health-related quality of life (HRQoL) and anxiety levels. METHODS: We included a random subgroup of all IPMN patients undergoing a follow-up check-up at Helsinki University Hospital (HUH) between August 2017 and November 2018. Patients were asked to complete the 15D HRQoL and state-trait anxiety inventory (STAI) questionnaires just before and three months after an IPMN control. RESULTS: Among 899 patients in IPMN follow-up, 232 participated. The 15D HRQoL results showed differences in some IPMN patients' 15 analyzed dimensions compared to a sex- and age-standardized general population cohort, but the clinical relevance of these differences appear doubtful. We detected no significant difference in the anxiety levels determined using the STAI questionnaires before or three months after the IPMN control. CONCLUSION: Surveillance should be less harmful than the risk of disease. Among our patients, the recommended IPMN follow-up carried minimal negative impact on patients' HRQoL or anxiety levels. This result is important, because the number of patients under IPMN surveillance is rapidly increasing and the cancer risk among the majority of these patients remains small. TRIAL REGISTRATION: The Surgical Ethics Committee of Helsinki University Hospital approved this study (Dnro HUS 475/2017) and it was registered at ClinicalTrials.gov (NCT03131076) before patient enrollment began.

Five-year Survival after McKeown Compared to Ivor-Lewis Esophagectomy for Esophageal Cancer: A Population-based Nationwide Study in Finland.

OBJECTIVE: The aim of study was to compare overall 5-year survival of esophageal cancer patients undergoing transthoracic esophagectomy with either neck or intrathoracic anastomosis, that is, McKeown and Ivor-Lewis esophagectomy. BACKGROUND: No national studies comparing long-term survival after McKeown and ivor-Lewis esophagectomies in the West exist. METHODS: This population-based nationwide study included all curatively intended transthoracic esophagectomies for esophageal adenocarcinoma or squamous cell carcinoma in Finland in 1987 to 2016, with follow-up until December 31, 2019. Cox proportional hazard models provided hazard ratios (HR) with 95% confidence intervals (ci) of all-cause 5-year mortality. The results were adjusted for age, sex, year of the operation, comorbidities, histology, stage, and neoadjuvant treatment. Adjusted model 2 included also tumor location and lymph node yield. RESULTS: A total of 990 patients underwent McKeown (n = 278) or Ivor-Lewis (n = 712) esophagectomy The observed overall 5-year survival was 43.1% after McKeown, and 45.9% after Ivor-Lewis esophagectomy. McKeown esophagectomy was not associated with the overall 5-year mortality (adjusted HR 1.11, 95% CI: 0.89-1.38), compared to Ivor-Lewis esophagectomy. Additional adjustment for tumor location and lymphadenectomy further attenuated the point estimate (HR 1.06, 95% CI: 0.85-1.33). Surgical approach was not associated with 90-day mortality rate (adjusted HR 1.15, 95% CI: 0.67-1.97). CONCLUSIONS: This population-based nationwide study suggests that overall 5-year survival or 90-day survival with McKeown and Ivor-Lewis esopha-gectomy for esophageal cancer are comparable.

Mono- and biallelic germline variants of DNA glycosylase genes in colon adenomatous polyposis families from two continents.

Recently, biallelic germline variants of the DNA glycosylase genes MUTYH and NTHL1 were linked to polyposis susceptibility. Significant fractions remain without a molecular explanation, warranting searches for underlying causes. We used exome sequencing to investigate clinically well-defined adenomatous polyposis cases and families from Finland (N=34), Chile (N=21), and Argentina (N=12), all with known susceptibility genes excluded. Nine index cases (13%) revealed germline variants with proven or possible pathogenicity in the DNA glycosylase genes, involving NEIL1 (mono- or biallelic) in 3 cases, MUTYH (monoallelic) in 3 cases, NTHL1 (biallelic) in 1 case, and OGG1 (monoallelic) in 2 cases. NTHL1 was affected with the well-established, pathogenic c.268C>T, p.(Gln90Ter) variant. A recurrent heterozygous NEIL1 c.506G>A, p.(Gly169Asp) variant was observed in two families. In a Finnish family, the variant occurred in trans with a truncating NEIL1 variant (c.821delT). In an Argentine family, the variant co-occurred with a genomic deletion of exons 2 - 11 of PMS2. Mutational signatures in tumor tissues complied with biological functions reported for NEIL1. Our results suggest that germline variants in DNA glycosylase genes may occur in a non-negligible proportion of unexplained colon polyposis cases and may predispose to tumor development.

Long-Term Survival After Transhiatal Versus Transthoracic Esophagectomy: A Population-Based Nationwide Study in Finland.

BACKGROUND: No population-based studies comparing long-term survival after transhiatal esophagectomy (THE) and transthoracic esophagectomy (TTE) exist. This study aimed to compare the 5-year survival of esophageal cancer patients undergoing THE or TTE in a population-based nationwide setting. METHODS: This study included all curatively intended THE and TTE for esophageal cancer in Finland during 1987-2016, with follow-up evaluation until 31 December 2019. Cox proportional hazard models provided hazard ratios (HRs) with 95% confidence intervals (CIs) of 5-year and 90-day mortality. The results were adjusted for age, sex, year of operation, comorbidities, histology, neoadjuvant treatment, and pathologic stage. RESULTS: A total of 1338 patients underwent THE (n = 323) or TTE (n = 1015). The observed 5-year survival rate was 39.3% after THE and 45.0% after TTE (p = 0.072). In adjusted model 1, THE was not associated with greater 5-year mortality (HR 0.99; 95% CI 0.82-1.20) than TTE. In adjusted model 2, including T stage instead of pathologic stage, the 5-year mortality hazard rates after THE (HR 0.87, 95% CI 0.72-1.05) and TTE were comparable. The 90-day mortality rate for THE was higher than for TTE (adjusted HR 0.72; 95% CI 0.45-1.14). In subgroup analyses, no differences between THE and TTE were observed in Siewert II gastroesophageal junction cancers, esophageal cancers, or pN0 tumors, nor in the comparison of THE and TTE with two-field lymphadenectomy. The sensitivity analysis, including patients with missing patient records, who underwent surgery during 1996-2016 mirrored the main analysis. CONCLUSIONS: This Finnish population-based nationwide study suggests no difference in 5-year or 90-day mortality after THE and TTE for esophageal cancer.