AUTHOR=Labania Lena , Zoughbor Sumaya , Ajab Suad , Olanda Marie , Shantour Sulaiman N. M. , Al Rasbi Zakeya 

TITLE=The associated risk of Blastocystis infection in cancer: A case control study

JOURNAL=Frontiers in Oncology

VOLUME=13

YEAR=2023

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2023.1115835

DOI=10.3389/fonc.2023.1115835

ISSN=2234-943X

ABSTRACT=<sec><title>Background</title><p><italic>Blastocystis</italic> is an anaerobic intestinal protozoan. Nine <italic>Blastocystis</italic> subtypes (STs) were detected in humans. A subtype-dependent association between <italic>Blastocystis</italic> and different cancer types has been debated in many studies. Thus, this study aims to assess the possible association between <italic>Blastocystis</italic> infection and cancer, especially colorectal cancer (CRC). We also screened the presence of gut fungi and their association with <italic>Blastocystis</italic>.</p></sec><sec><title>Methods</title><p>We used a case-control design; cancer patients and cancer-free (CF) participants. The cancer group was further sub-group into CRC group and cancers outside the gastrointestinal tract (COGT) group. Macroscopic and microscopic examinations were performed to identify intestinal parasites in participants’ stool samples. Molecular and phylogenetic analyses were conducted to identify and subtype <italic>Blastocystis</italic>. Furthermore, gut fungi were investigated molecularly.</p></sec><sec><title>Results</title><p>104 stool samples were collected and matched between CF (n=52) and cancer patients (n=52); CRC (n=15) and COGT (n=37). As anticipated, <italic>Blastocystis</italic> prevalence was significantly higher among CRC patients (60%, P=0.002) and insignificant in COGT patients (32.4%, <italic>P</italic>=0.161) compared to CF group (17.3%). The most common subtypes were ST2 among cancer group and ST3 in the CF group.</p></sec><sec><title>Conclusion</title><p>Cancer patients have a higher risk of <italic>Blastocystis</italic> infection compared to CF individuals (OR=2.98, <italic>P</italic>=0.022). Increased risk of <italic>Blastocystis</italic> infection was associated with CRC patients (OR=5.66, <italic>P</italic>=0.009). Nevertheless, further studies are required to understand the underlying mechanisms of <italic>Blastocystis</italic> and cancer association.</p></sec>