Validering av immunologiska markörer för screening av magsäckscancer i låginkomstländer Validation of immunological markers for use in screening of stomach cancer in low-income settings Kan forskning om cancer verkligen vara till nytta för fattiga människor i låginkomstländer?    Ja, trots vad de flesta tror, håller cancer alltmer på att bli en sjukdom som till största delen drabbar fattiga. År 2008 uppskattade WHO att 57 % av cancerfallen och 65 % av dödsfallen i cancer skedde i de mer lågutvecklade länderna. Problemet förväntas dessutom öka de närmaste decennierna.    Magsäckscancer är ett stort hälsoproblem i världen. Det är den tredje vanligaste dödsorsaken i världen, med ca 700 000 dödsfall per år. Mer än 70 % av dessa återfinns i låg- och medelinkomstländer.  I de länder som räknas som mest underutvecklade beräknas det att det varje år avlider mer än 17 000 människor pga magsäckscancer. Som jämförelse orsakade Ebolaepidemin i västafrika 2014-2015 ca 10 000 dödsfall.    Magsäckscancer orsakas oftast av en kronisk infektion med magsäcksbakterien Helicobacter pylori. Infektionen är vanligast i de fattigare länderna i världen. De flesta som är infekterade utvecklar inte några allvarliga symptom, men 1-3 % drabbas av magsäckscancer. En orsak till den höga dödligheten i sjukdomen är att den är svårupptäckt, och därför oftast upptäcks för sent, när tumörcellerna redan har spridit sig i kroppen. Vid tidigare upptäckt kan man behandla genom att operera bort tumören, och man har då en mycket bättre chans att överleva sjukdomen.    Projektets målsättning är att ta fram en metod eller ett test för att upptäcka magsäckscancer med ett blod- eller salivprov, och testet ska vara så billigt att det går att använda i stor skala i de fattigare länder där man löper stor risk att drabbas av magsäckscancer. Om vi lyckas med målsättningen kommer vi att kunna bidra till att dödligheten i magsäckscancer minskar i de länder där risken för sjukdomen är hög. Would research on cancer really be of benefit for the most underdeveloped countries?    Yes, despite common belief, cancer is increasingly becoming a disease preferentially affecting the poor. In 2008, WHO estimated that 57 % of cancer cases and 65 % of cancer deaths occurred in less developed countries, and the magnitude of the problem in low-income countries is expected to increase during coming decades.    Stomach cancer is a major health problem. It is the third most common cause of cancer death in the world, affecting around 700 000 people every year, the large majority (> 70 %) in low- and middle-income countries. In the countries defined as "least developed" or "other low-income", it is estimated that 17 350 stomach cancer deaths currently occur each year. As a comparison, the Ebola epidemic of West Africa in 2014 caused 9980 deaths.    Stomach cancer mortality to a high degree affects the poorest people in all countries, regardless of whether these individuals reside in a country defined as a low-income country or not. Thus, large numbers of deaths by stomach cancer occur among the most poor populations of low-middle income developing countries of Latin America and Asia.     The disease is most often caused by a chronic infection with the bacterium Helicobacter pylori, which is highly prevalent in less developed areas of the world. H. pylori infection is not a sufficient cause for stomach cancer, but other factors such as smoking and a poor diet add to the effects of the infection to increase risk of cancer development. Overall, around 2-3 % of infected individuals develop stomach cancer over the course of their life-time.    An important barrier to improved health in the stomach cancer area is the fact that stomach cancer has very diffuse symptoms and therefore is diagnosed at a late stage. When the disease is discovered early, significantly increased long-term survival can be achieved by surgical treatment. A simple and low-cost method that can detect stomach cancer by screening in high-incidence countries would therefore be strongly beneficial.     There are currently no biomarkers (identified biological markers) or screening tools available for stomach cancer. The current research project aims to establish and validate such a tool. The overall aim of the project is to develop a low-cost and minimally invasive screening test that can be used in low-income settings for identification of individuals affected by gastric cancer at an early stage of the disease. We propose to do this by detecting the natural biomarkers of the immune system: antibodies, using a low-cost lateral-flow assay. We will identify antibody signatures to H. pylori peptides that can be used to identify gastric cancer using blood or saliva samples. Our proposal rests on the fact that the immune response to H. pylori differs between individuals developing stomach cancer and individuals without cancer.    The proposed project is an important part of an international collaboration between highly skilled research groups in Sweden, Nicaragua, Australia, Canada, Italy and USA, which are very well suited to conduct the outlined experiments due to long-standing expertise in mucosal immunology, immune assay development, H. pylori infection, oncology and cancer diagnosis.    Specific aims of the project:  1. To identify a signature of Helicobacter pylori peptides that can be used as a screening tool to identify individuals with stomach cancer  2. To set up a low-cost test kit that allows use of this screening signature in low-income settings   3. To establish whether salivary samples can replace serum/plasma for screening    If successful, our project will enable early detection and may thereby contribute to increased survival in stomach cancer disease in many of the poor countries around the world.