Two-year clinico-biological feedback in Overseas France and French-speaking territories during Covid-19 pandemic / Retour d'expériences clinico-biologiques en Outre-mer et en Francophonie après deux années de pandémie Covid-19

The French Society of Clinical Biology (SFBC) set up a working group "Biochemical markers of Covid-19" whose main objective is to review, analyse and monitor biological prescriptions according to the patient's care path. This study covers all public and private sectors of medical biology in metropolitan France and overseas and extends to the French-speaking world. We present a summary of feedbacks after 2 years of the pandemic. At the early stage of Covid-19, with regard to the regions surveyed, a common symptomatology with local zoonosis (dengue fever, zika, malaria, leptospirosis, etc.) complicates the diagnosis of Covid-19. At a more advanced stage, it is a question of managing an influx of patients suffering from acute respiratory distress syndrome. In this case, the biology is then simpler and delocalized medical biology devices have proven their effectiveness. As a result, ICU clinicians can better manage the frequent comorbidities encountered in these regions: obesity, diabetes, chronic renal failure, cardiovascular diseases.

La Société française de biologie clinique (SFBC) a mis en place un groupe de travail « Marqueurs biochimiques de Covid-19 ¼ dont l'objectif principal est de revoir, d'analyser et de suivre les prescriptions biologiques en fonction du parcours de soins du patient. Cette étude couvre tous les secteurs publics et privés de la biologie médicale en métropole et en Outre-mer et s'étend à la Francophonie. Nous présentons une synthèse des retours d'expériences après 2 ans de pandémie. Au stade précoce de la Covid-19, pour les régions interrogées, une symptomatologie commune avec des zoonoses locales (dengue, zika, paludisme, leptospirose…) complique le diagnostic de la Covid-19. À un stade plus avancé, il s'agit de gérer un afflux de patients atteints de syndrome de détresse respiratoire aiguë. La biologie est alors plus simple, et les dispositifs de biologie médicale délocalisée ont prouvé leur efficacité. De ce fait, les réanimateurs peuvent mieux gérer les comorbidités fréquentes rencontrées dans ces régions : obésité, diabète, insuffisance rénale chronique ou maladies cardiovasculaires.

Somatic substitution signature as an innovative tool in lung cancer diagnosis.

Diagnosis of lung cancer can sometimes be challenging and is of major interest since effective molecular-guided therapies are available. Compounds of tobacco smoke may generate a specific substitutional signature in lung, which is the most exposed organ. To predict whether a tumor is of lung origin or not, we developed and validated the EASILUNG (Exome And SIgnature LUNG) test based on the relative frequencies of somatic substitutions on coding non-transcribed DNA strands from whole-exome sequenced tumors. Data from 7,796 frozen tumor samples (prior to any treatment) from 32 TCGA solid cancer groups were used for its development. External validation was carried out on a local dataset of 196 consecutive routine exome results. Eight out of the 12 classes of substitutions were required to compute the EASILUNG signature that demonstrated good calibration and good discriminative power with a sensitivity of 83% and a specificity of 72% after recalibration on the external validation dataset. This innovative test may be helpful in medical decision-making in patients with unknown primary tumors potentially of lung origin and in the diagnosis of lung cancer in smokers.