Molecular Basis of Mismatch Repair Protein Deficiency in Tumors from Lynch Suspected Cases with Negative Germline Test Results

Some 10–50% of Lynch-suspected cases with abnormal immunohistochemical (IHC) staining remain without any identifiable germline mutation of DNA mismatch repair (MMR) genes. MMR proteins form heterodimeric complexes, giving rise to distinct IHC patterns when mutant. Potential reasons for not finding a germline mutation include involvement of an MMR gene not predicted by the IHC pattern, epigenetic mechanism of predisposition, primary mutation in another DNA repair or replication-associated gene, and double somatic MMR gene mutations. We addressed these possibilities by germline and tumor studies in 60 Lynch-suspected cases ascertained through diagnostics (n = 55) or research (n = 5). All cases had abnormal MMR protein staining in tumors but no point mutation or large rearrangement of the suspected MMR genes in the germline. In diagnostic practice, MSH2/MSH6 (MutS Homolog 2/MutS Homolog 6) deficiency prompts MSH2 mutation screening; in our study, 3/11 index individuals (27%) with this IHC pattern revealed pathogenic germline mutations in MSH6. Individuals with isolated absence of MSH6 are routinely screened for MSH6 mutations alone; we found a predisposing mutation in MSH2 in 1/7 such cases (14%). Somatic deletion of the MSH2-MSH6 region, joint loss of MSH6 and MSH3 (MutS Homolog 3) proteins, and hindered MSH2/MSH6 dimerization offered explanations to misleading IHC patterns. Constitutional epimutation hypothesis was pursued in the MSH2 and/or MSH6-deficient cases plus 38 cases with MLH1 (MutL Homolog 1)-deficient tumors; a primary MLH1 epimutation was identified in one case with an MLH1-deficient tumor. We conclude that both MSH2 and MSH6 should be screened in MSH2/6- and MSH6-deficient cases. In MLH1-deficient cases, constitutional epimutations of MLH1 warrant consideration

Advising and limiting medical treatment during phone consultation : a prospective multicentre study in HEMS settings

Background We investigated paramedic-initiated consultation calls and advice given via telephone by Helicopter Emergency Medical Service (HEMS) physicians focusing on limitations of medical treatment (LOMT). Methods A prospective multicentre study was conducted on four physician-staffed HEMS bases in Finland during a 6-month period. Results Of all 6115 (mean 8.4/base/day) paramedic-initiated consultation calls, 478 (7.8%) consultation calls involving LOMTs were included: 268 (4.4%) cases with a pre-existing LOMT, 165 (2.7%) cases where the HEMS physician issued a new LOMT and 45 (0.7%) cases where the patient already had an LOMT and the physician further issued another LOMT. The most common new limitation was a do-not-attempt cardiopulmonary resuscitation (DNACPR) order (n = 122/210, 58%) and/or 'not eligible for intensive care' (n = 96/210, 46%). In 49 (23%) calls involving a new LOMT, termination of an initiated resuscitation attempt was the only newly issued LOMT. The most frequent reasons for issuing an LOMT during consultations were futility of the overall situation (71%), poor baseline functional status (56%), multiple/severe comorbidities (56%) and old age (49%). In the majority of cases (65%) in which the HEMS physician issued a new LOMT for a patient without any pre-existing LOMT, the physician felt that the patient should have already had an LOMT. The patient was in a health care facility or a nursing home in half (49%) of the calls that involved issuing a new LOMT. Access to medical records was reported in 29% of the calls in which a new LOMT was issued by an HEMS physician. Conclusion Consultation calls with HEMS physicians involving patients with LOMT decisions were common. HEMS physicians considered end-of-life questions on the phone and issued a new LOMT in 3.4% of consultations calls. These decisions mainly concerned termination of resuscitation, DNACPR, intubation and initiation of intensive care.Peer reviewe

Well-being at work among helicopter emergency medical service personnel in Finland

Personnel engaged in emergency medical services (EMS) and in helicopter emergency medical services (HEMS) perform challenging missions 24/7. This underlines the importance of overall well-being at work among these personnel. Only healthy personnel can successfully perform challenging HEMS missions in the long run. Fatigue due to an imbalance between overall strain and recovery is an occupational hazard that may compromise both well-being at work and operational and patient safety in HEMS settings. However, there are no evidence-based recommendations available on how to mitigate fatigue at HEMS work. For this reason, it is important to create a comprehensive picture of HEMS personnel’s overall well-being at work, including on-duty fatigue, at the national level. The research aim of the present study was to assess the overall well-being at work among HEMS personnel in Finland, with the main emphasis on fatigue and the balance between strain and recovery. To make the results as useful as possible for development actions, different occupational groups, duties, and task load levels were considered in the assessment. The development aim of the present study was to a) identify the main development needs to promote the overall balance between strain and recovery in HEMS professionals and b) introduce a future improvement plan to achieve this goal

Somatic mutation profiles as molecular classifiers of ulcerative colitis-associated colorectal cancer

Ulcerative colitis increases colorectal cancer risk by mechanisms that remain incompletely understood. We approached this question by determining the genetic and epigenetic profiles of colitis-associated colorectal carcinomas (CA-CRC). The findings were compared to Lynch syndrome (LS), a different form of cancer predisposition that shares the importance of immunological factors in tumorigenesis. CA-CRCs (n = 27) were investigated for microsatellite instability, CpG island methylator phenotype and somatic mutations of 999 cancer-relevant genes ("Pan-cancer" panel). A subpanel of "Pan-cancer" design (578 genes) was used for LS colorectal tumors (n = 28). Mutational loads and signatures stratified CA-CRCs into three subgroups: hypermutated microsatellite-unstable (Group 1, n = 1), hypermutated microsatellite-stable (Group 2, n = 9) and nonhypermutated microsatellite-stable (Group 3, n = 17). The Group 1 tumor was the only one with MLH1 promoter hypermethylation and exhibited the mismatch repair deficiency-associated Signatures 21 and 15. Signatures 30 and 32 characterized Group 2, whereas no prominent single signature existed in Group 3. TP53, the most common mutational target in CA-CRC (16/27, 59%), was similarly affected in Groups 2 and 3, but DNA repair genes and Wnt signaling genes were mutated significantly more often in Group 2. In LS tumors, the degree of hypermutability exceeded that of the hypermutated CA-CRC Groups 1 and 2, and somatic mutational profiles and signatures were different. In conclusion, Groups 1 (4%) and 3 (63%) comply with published studies, whereas Group 2 (33%) is novel. The existence of molecularly distinct subgroups within CA-CRC may guide clinical management, such as therapy options.Peer reviewe

Cerebral oxygen desaturation events during and functional outcomes after prehospital anaesthesia : A prospective pilot study

Background: During prehospital anaesthesia, oxygen delivery to the brain might be inadequate to match the oxygen consumption, with unknown long-term functional outcomes. We aimed to evaluate the feasibility of monitoring cerebral oxygenation during prehospital anaesthesia and determining the long-term outcomes. Methods: We performed a prospective observational feasibility study in two helicopter emergency medical services units. Frontal lobe regional oxygen saturation (rSO(2)) of adult patients undergoing prehospital anaesthesia was monitored with near-infrared spectroscopy (NIRS) by a Nonin H500 oximeter. The outcome was evaluated with a modified Rankin Scale (mRS) at 30 days and 1 year. Health-related quality of life (HRQoL) was measured with a 15D instrument at 1 year. Results: Of 101 patients enrolled, 83 were included. The mean baseline rSO(2) was 79% (73-84). Desaturation for at least 5 min to rSO(2) below 50% or a decrease of 10% from baseline occurred in four (5%, 95% CI 2%-12%) and 19 (23%, 95% CI 15-93) patients. At 1 year, 32 patients (53%, 95% CI 41-65) achieved favourable neurological outcomes. The median 15D score was 0.889 (Q1-Q3, 0.796-0.970). Conclusion: Monitoring cerebral oxygenation with a hand-held oximeter during prehospital anaesthesia and collecting data on functional outcomes and HRQoL are feasible. Only half of the patients achieved a favourable functional outcome. The effects of cerebral oxygenation on outcomes during prehospital critical care need to be assessed in future studies.Peer reviewe

The first seven years of nationally organized helicopter emergency medical services in Finland - the data from quality registry

Background: Helicopter Emergency Medical Services (HEMS) play an important role in prehospital care of the critically ill. Differences in funding, crew composition, dispatch criteria and mission profile make comparison between systems challenging. Several systems incorporate databases for quality control, performance evaluation and scientific purposes. FinnHEMS database was incorporated for such purposes following the national organization of HEMS in Finland 2012. The aims of this study are to describe information recorded in the database, data collection, and operational characteristics of Finnish HEMS during 2012-2018. Methods: All dispatches of the six Finnish HEMS units recorded in the national database from 2012 to 2018 were included in this observational registry study. Five of the units are physician staffed, and all are on call 24/7. The database follows a template for uniform reporting in physician staffed pre-hospital services, exceeding the recommended variables of relevant guidelines. Results: The study included 100,482 dispatches, resulting in 33,844 (34%) patient contacts. Variables were recorded with little or no missing data. A total of 16,045 patients (16%) were escorted by HEMS to hospital, of which 2239 (2%) by helicopter. Of encountered patients 4195 (4%) were declared deceased on scene. The number of denied or cancelled dispatches was 66,638 (66%). The majority of patients were male (21,185, 63%), and the median age was 57.7 years. The median American Society of Anesthesiologists Physical Scale classification was 2 and Eastern Cooperative Oncology Group performance class 0. The most common reason for response was trauma representing 26% (8897) of the patients, followed by out-of-hospital cardiac arrest 20% (6900), acute neurological reason excluding stroke 13% (4366) and intoxication and related psychiatric conditions 10% (3318). Blunt trauma (86%, 7653) predominated in the trauma classification. Conclusions: Gathering detailed and comprehensive data nationally on all HEMS missions is feasible. A national database provides valuable insights into where the operation of HEMS could be improved. We observed a high number of cancelled or denied missions and a low percentage of patients transported by helicopter. The medical problem of encountered patients also differs from comparable systems.Peer reviewe

Loppuraportti: Valtakunnallinen selvitys ensihoitopalvelun toiminnasta

Selvitys perustuu pääasiassa Hätäkeskuslaitokselta saatuun ensihoitotehtäviä koskevaan aineistoon vuosilta 2010 – 2014. Tavoitteena oli tuottaa tietoa ensihoitopalvelun toiminnasta sekä toiminnan muutoksista. Selvityksessä todettiin, että ensihoitopalvelun nykyiset tiedot eivät ole kansallisella tasolla luotettavia, mikä haittaa toiminnan analysointia ja kehittämistä merkittävästi. Nykyinen päivystyksellisten potilasvirtojen ohjaus ja ensihoitoresurssien käyttö toteutuvat epätarkoituksenmukaisesti. Ensihoitopalveluun näyttää tulleen pysyvänä mallina potilaiden hoidon tarpeen tarkempi arvio ja palvelun kohdistuminen myös hoito- ja hoivalaitoksiin. Ensihoitopalveluiden kustannuskehitys ei ole johtunut yksinomaan ensihoidon järjestämisvastuun siirrosta kunnilta sairaanhoitopiireille. Ensihoitopalveluun tarvitaan kansallinen tietovaranto, josta saadaan luotettavasti toiminta- ja kustannustiedot ja johon perustuen voidaan toimintaa johtaa tiedolla. Tietovarannon avulla on kyettävä yhdistämään päivystyksellisten potilaiden koko hoitoketjun tiedot hätäkeskustoiminnasta lopulliseen hoitopaikkaan ja hoitojaksoon hoidon vaikuttavuuden ja tuloksellisuuden seuraamiseksi. Resurssien käyttöä tulee parantaa johtamalla toimintaa yhteistyöalueittain ja toteuttamalla kansallinen toimialan puhelinneuvontapalvelu. Myös ensihoitohenkilöstön koulutussuunnittelussa on huomioitava muuttunut toimintakenttä. Sosiaali- ja terveydenhuollon päivystysjärjestelmää on kehitettävä tärkeänä osana yhteiskunnan kokonaisturvallisuutta

Valtakunnallinen selvitys ensihoitopalvelun toiminnasta : Väliraportti 2

Sosiaali- ja terveysministeriön päätöksellä käynnistettiin valtakunnallinen selvitys ensihoitopalvelun tehtävistä. Selvityksen perustana on maan kaikki hätäkeskuksista tulleet ensihoitotehtävät viiden vuoden ajalta. Tällä hetkellä emme pysty kansallisesti tuottamaan ensihoitopalvelun toiminnan keskeisiä tun-nuslukuja, eikä järjestelmässä tapahtuneiden muutosten vaikuttavuutta voida siten myöskään luotettavasti arvioida. On välttämätöntä luoda kansallinen ensihoitopalvelun tietovaranto, jotta pystymme suunnittelemaan ja ohjaamaan resurssien käyttöä tarkoituksenmukaisesti ja reaaliaikaisesti. Siihen tulee kerätä sekä ensihoitopalvelua kuvaavat kansalliset operatiiviset tiedot (hätäkeskustietojärjestelmä, viranomaisten kenttäjärjestelmä) että niihin yhdistettyinä kansallisesti kerätyt potilastiedot (kansallinen ensihoitokertomus, Potilastiedon arkisto). Ensihoitopalvelun suunnittelussa tulee huomioida sekä tehtävävolyymin muuttuminen pelkäs-tään hätätilapotilaista kohti laajempaa päivystyspotilaiden kirjoa että nykyistä paremmin verkottumisesta muihin sosiaali- ja terveydenhuollon lähipalveluihin. Hätäkeskusten toiminta on päivystyksellisten potilasvirtojen ohjauspaikkana aliarvioitu. Sosiaali- ja terveystoimen rakenneuudistuksen yhteydessä tulee uudelleen arvioida hätäkeskusten rajapinnassa oleva toiminta. Tehtävien riskinarviointi ja tarkoituksenmukainen resurssien käyttö edellyttävät sosiaali- ja terveystoimen päivystystoiminnan johto- ja koordinaatiokeskusten perustamista. Näihin keskuksiin keskitettäisiin myös kansallinen kansalaisten terveydenhuollon puhelinneuvonta ja -ohjaus

Biallelic germline nonsense variant of MLH3 underlies polyposis predisposition

Purpose: Some 10% of familial adenomatous polyposis (FAP) and 80% of attenuated polyposis (AFAP) cases remain molecularly unexplained. We scrutinized such cases by exome-wide and targeted methods to search for novel susceptibility genes. Methods: Exome sequencing was conducted on 40 unexplained (mainly sporadic) cases with FAP or AFAP from Finland. The DNA mismatch repair (MMR) gene MLH3 (MutL Homolog 3) was pinpointed and prompted a subsequent screen of similar to 1000 Swedish patients referred to clinical panel sequencing for colon tumor susceptibility. Results: Three homozygous carriers of a truncating variant in MLH3, c.3563C>G, p.Ser1188Ter, were identified among the index cases from the Finnish series. An additional biallelic carrier of the same variant was present in the Swedish series. All four patients shared a 0.8-Mb core haplotype around MLH3, suggesting a founder variant. Colorectal polyps from variant carriers showed no instability at mono-, di-, tri-, or tetranucleotide repeats, in agreement with previous findings of a minor role of MLH3 in MMR. Multiple loci were affected by loss of heterozygosity, suggesting chromosomal instability. Conclusion: Our results show that a biallelic nonsense variant of MLH3 underlies a novel syndrome with susceptibility to classical or attenuated adenomatous polyposis and possibly extracolonic tumors, including breast cancer.Peer reviewe

Thyroid carcinomas that occur in familial adenomatous polyposis patients recurrently harbor somatic variants in APC, BRAF, and KTM2D

Background: Familial adenomatous polyposis (FAP) is a condition typically caused by pathogenic germline mutations in the APC gene. In addition to colon polyps, individuals with FAP have a substantially increased risk of developing papillary thyroid cancer (PTC). Little is known about the events underlying this association, and the prevalence of somatic "second-hit" mutations in APC is controversial. Methods: Whole-genome sequencing was performed on paired thyroid tumor and normal DNA from 12 FAP patients who developed PTC. Somatic mutation profiles were compared with clinical characteristics and previously sequenced sporadic PTC cases. Germline variant profiling was performed to assess the prevalence of variants in genes previously shown to have a role in PTC predisposition. Results: All 12 patients harbored germline mutations in APC, consistent with FAP. Seven patients also had somatic mutations in APC, and seven patients harbored somatic mutations in KMT2D, which encodes a lysine methyl transferase. Mutation of these genes is extremely rare in sporadic PTCs. Notably, only two of the tumors harbored the somatic BRAF p.V600E mutation, which is the most common driver mutation found in sporadic PTCs. Six tumors displayed a cribriform-morular variant of PTC (PTC-CMV) histology, and all six had somatic mutations in APC. Additionally, nine FAP-PTC patients had rare germline variants in genes that were previously associated with thyroid carcinoma. Conclusions: Our data indicate that FAP-associated PTCs typically have distinct mutations compared with sporadic PTCs. Roughly half of the thyroid cancers that arise in FAP patients have somatic "second-hits" in APC, which is associated with PTC-CMV histology. Somatic BRAF p.V600E variants also occur in some FAP patients, a novel finding. We speculate that in carriers of heterozygous pathogenic mutations of tumor suppressor genes such as APC, a cooperating second-hit somatic variant may occur in a different gene such as KTM2D or BRAF, leading to differences in phenotypes. The role of germline variance in genes other than APC (9 of the 12 patients in this series) needs further research.Peer reviewe