Insights into the Association Between Blastocystis Infection and Colorectal Cancer.

Area of Science:

• Medical Parasitology
• Gastroenterology
• Oncology

Background:

• The relationship between Blastocystis spp. infection and colorectal cancer (CRC) remains unclear.
• Blastocystis spp. is a common intestinal protozoan parasite with varied clinical presentations.

Purpose of the Study:

• To investigate Blastocystis infection prevalence in CRC patients.
• To assess the impact of chemotherapy on Blastocystosis in CRC patients.
• To explore potential associations between CRC and specific Blastocystis subtypes (STs).

Main Methods:

• 150 participants were categorized into three groups: CRC patients without chemotherapy (n=50), CRC patients undergoing chemotherapy (n=50), and healthy controls (n=50).
• Microscopy, culture, PCR, PCR-restriction fragment length polymorphism (RFLP), and sequencing were employed for Blastocystis detection and subtyping.

Main Results:

• Blastocystis spp. infection was significantly higher in CRC patients (40% in Group I, 32% in Group II) compared to controls (12%).
• PCR-STS analysis identified prevalent subtypes as ST1 (52%) and ST3 (24%), with no significant difference in ST distribution among the groups.
• Blastocystis infection was associated with symptom development, regardless of CRC status or chemotherapy treatment.

Conclusions:

• Blastocystis infection shows a higher prevalence in colorectal cancer patients, indicating a potential association.
• Blastocystis may function as an opportunistic pathogen, contributing to symptoms independently of CRC.
• The complex pathogenicity of Blastocystis is not solely attributed to specific subtypes (STs).