Insights into the Association Between Blastocystis Infection and Colorectal Cancer

• Published in: Acta parasitologica Vol. 70; no. 4; p. 156
• Main Authors: Shehab, Amel, El-Sayad, Mona, Allam, Amal, Mohamed, Bassam, Elsaka, Rasha, Ibrahim, Marwa, El-Latif, Naglaa Abd
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 14.07.2025; Springer Nature B.V
• Subjects: Adult; Aged; Aged, 80 and over; Animal Systematics/Taxonomy/Biogeography; Biomedical and Life Sciences; Biomedicine; Blastocystis; Blastocystis - classification; Blastocystis - genetics; Blastocystis - isolation & purification; Blastocystis Infections - complications; Blastocystis Infections - drug therapy; Blastocystis Infections - epidemiology; Blastocystis Infections - parasitology; Cancer; Case-Control Studies; Chemotherapy; Colorectal cancer; Colorectal carcinoma; Colorectal Neoplasms - complications; Colorectal Neoplasms - epidemiology; Colorectal Neoplasms - parasitology; Ecology; Feces - parasitology; Female; Humans; Infections; Male; Medical Microbiology; Microbiology; Middle Aged; Opportunist infection; Parasitology; Pathogenicity; Polymerase Chain Reaction; Polymorphism; Polymorphism, Restriction Fragment Length; Prevalence; Restriction fragment length polymorphism; ST distribution; spp; PCR-STS analysis; PCR-RFLP analysis; Colorectal cancer; Blastocystis spp
• ISSN: 1230-2821; 1896-1851; 1896-1851
• DOI: 10.1007/s11686-025-01079-y

Objective Given the unclear relationship between Blastocystis spp. infection and colorectal cancer (CRC), this study aimed to provide insight into Blastocystis infection, assess the effect of chemotherapy on Blastocystosis in CRC patients, and explore potential links between CRC and Blastocystis subtypes (STs). Subjects A total of 150 participants were divided into three groups: Group I (50 CRC patients not receiving chemotherapy), Group II (50 CRC patients who were receiving chemotherapy), and Group III (50 healthy, age- and sex-matched controls). Results Blastocystis spp. was detected in 42 cases through microscopy and culture, with infection rates higher in Group I (40%) and Group II (32%) compared to the control group (12%). Among all participants, 86 were asymptomatic, while 64 experienced symptoms. PCR analysis confirmed Blastocystis in 26 out of the 42 cases. PCR-restriction fragment length polymorphism (RFLP) analysis identified 60% of isolates as Group A and 16% as Group C, while sequencing later confirmed that 24% belonged to Group B. PCR-sequence-tagged site (STS) analysis revealed five STs (ST1, ST2, ST3, ST5, and ST7), with ST1 (52%) and ST3 (24%) identified as the most prevalent STs. Conclusion Blastocystis infection was significantly higher in CRC patients, suggesting a possible association with the disease. It appears to act as an opportunistic pathogen, contributing to symptom development regardless of CRC. The absence of significant differences in ST distribution across groups indicates that Blastocystis pathogenicity is complex and not exclusively linked to specific STs.