Öncü Öner T.Karabey M.Can H.Değirmenci Döşkaya A.Karakavuk M.Gül A.Köseoğlu A.E.Döşkaya M.Ün C.Gürüz A.Y.Kaya S.Pektaş B.Aksoy Gökmen A.2024-07-222024-07-2220220001706Xhttp://akademikarsiv.cbu.edu.tr:4000/handle/123456789/12568Blastocystis sp. is a common enteric protist found in humans and many other animals. Although the clinical relevance of Blastocystis sp. is currently fully unknown for humans, the prevalence of Blastocystis and subtypes are investigated in immunocompetent individuals presenting with symptoms like diarrhea or immunocompromised individuals including cancer patients. In this comprehensive study, the prevalence of Blastocystis sp. and subtypes were investigated in patients (n=94) with different types of malignant solid tumors using PCR targeting SSU rDNA gene and sequencing. All patients were undergoing chemotherapy and had diarrhea. According to obtained results, 46 patients were found to be Blastocystis positive and the molecular prevalence was detected as 48.9%. Among the positive specimens, 43 (43/46; 93.5%) of them were successfully subtyped. ST4 was the most predominant subtype and detected in 24 (55.8%) patients, followed by ST1 (11 patients, 25.6%) and ST3 (8 patients, 18.6%). In the colon cancer group, which had the highest number of patients, Blastocystis sp. was detected with a higher prevalence rate of 61.5% compared with the prevalence rate (48.9%) of all patients. Interestingly, ST3 was not detected in any of this patient group in contrast to ST4 and ST1. In conclusion, high prevalence of the Blastocystis in the immunocompromised patient groups shows the susceptibility of this patient group against any other infectious agents. © 2022EnglishAnimalsBlastocystisBlastocystis InfectionsDiarrheaDNA, ProtozoanFecesGenetic VariationHumansNeoplasmsPhylogenyPrevalenceTurkeyTurkeyantineoplastic agentribosome DNAprotozoal DNAcancerchemotherapydiarrheal diseasedisease prevalencemolecular analysispolymerase chain reactionadultagedArticleBlastocystisblastocystosiscancer chemotherapycancer patientcolon cancercontrolled studydiarrheafemalegene sequencehumanhuman cellmajor clinical studymalemolecular diagnosisnonhumanparasite identificationpolymerase chain reactionprevalencesolid malignant neoplasmstrain identificationTurkey (republic)animalblastocystosiscomplicationdiarrheafecesgenetic variationgeneticsneoplasmphylogenyturkey (bird)Article10.1016/j.actatropica.2022.106577