Publications by authors named "Ari Ristimaki"

The Esophageal Adenocarcinoma Study Group Europe (EACSGE) recently proposed a granular histologic classification of esophageal-esophago-gastric junctional adenocarcinomas (EA-EGJAs) based on the study of naïve surgically resected specimens that, when combined with the pTNM stage, is an efficient indicator of prognosis, molecular events, and response to treatment. In this study, we compared histologic classes of endoscopic biopsies taken before surgical resection with those of the surgical specimen, to evaluate the potential of the EACSGE classification at the initial diagnostic workup. A total of 106 EA-EGJA cases with available endoscopic biopsies and matched surgical resection specimens were retrieved from five Italian institutions.

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Article Synopsis
  • - This study analyzed the long-term survival rates of gastric cancer patients in Finland who underwent total or partial gastrectomy along with either splenectomy (removal of the spleen) or spleen preservation from 2005 to 2016.
  • - Data from 2,196 patients were examined, revealing a 5-year survival rate of 38.7% for patients with minor spleen injury, 39.7% for those with splenectomy due to injury, and 30.8% for splenectomy due to cancer, indicating that the method of spleen management significantly impacted survival outcomes.
  • - The results suggest that patients undergoing splenectomy for oncological reasons had worse survival rates compared to those
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Microsatellite unstable colorectal cancer (MSI-CRC) can arise through germline mutations in mismatch repair (MMR) genes in individuals with Lynch syndrome (LS), or sporadically through promoter methylation of the MMR gene MLH1. Despite the different origins of hereditary and sporadic MSI tumours, their genomic features have not been extensively compared. A prominent feature of MMR-deficient genomes is the occurrence of many indels in short repeat sequences, an understudied mutation type due to the technical challenges of variant calling in these regions.

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Background: The purpose of this study was to examine the rates of 90-day anastomotic complications and other postoperative complications after total or partial gastrectomy with antecolic versus retrocolic reconstruction in a population-based setting.

Methods: This population-based nationwide retrospective cohort study included all patients undergoing total or partial gastrectomy for gastric adenocarcinoma in Finland in 2005-2016, with follow-up until 31 December 2019. Logistic regression provided odds ratios (ORs) with 95% confidence intervals (CIs) of 90-day mortality.

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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.

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Background: This study aimed to examine the rate of delayed emptying and other 90-day postoperative complications after total, subtotal, and distal gastrectomies for gastric adenocarcinoma in a population-based setting.

Methods: This study included all patients who underwent total, subtotal, or distal gastrectomy for gastric cancer in Finland in 2005-2016, with follow-up until December 31, 2019. Logistic regression provided the odds ratios with 95% CIs of 90-day mortality.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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 BRAF wild-type and mutated subgroups ( = 10 in each subgroup), with each other and with those of paired non-neoplastic mucosal samples using mass spectrometry.

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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.

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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.

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Article Synopsis
  • Esophageal adenocarcinoma (EAC) is a serious cancer with rising rates, unclear causes, and low survival.
  • A study of 164 untreated EAC patients revealed 337 genetic variants, predominantly in the TP53 gene, which was linked to poorer survival outcomes.
  • Additionally, mutations in the HNF1alpha gene and gene fusions were identified, highlighting important genetic factors in EAC progression.
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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.

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Article Synopsis
  • The study investigates the impact of surveillance for intraductal papillary mucinous neoplasms (IPMNs) on patients' health-related quality of life (HRQoL) and anxiety levels.
  • A subgroup of 232 out of 899 patients completed HRQoL and anxiety questionnaires before and three months after follow-up, revealing minimal negative effects on their well-being.
  • The findings suggest that regular monitoring of patients with IPMNs is manageable and unlikely to significantly worsen their quality of life or anxiety, even as the number of patients under surveillance rises.
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Recently, biallelic germline variants of the DNA glycosylase genes and 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.

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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.

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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.

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Background: Wnt/β-catenin signaling is a highly conserved signaling pathway that regulates the transcription factor PROX1. The role of β-catenin and PROX1 in pancreatic cancer is ambiguous, as some studies have associated their expression with tumor regression and some with tumor progression.

Objective: We have investigated their expression in surgically treated pancreatic cancer patients receiving neoadjuvant therapy (NAT), and patients treated upfront with surgery (US).

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