[High prevalence of Cryptosporidium infection in colorectal cancer cases from Tunisia].

Abstract

Introduction: Colorectal cancer (CRC) is a major public health problem, including in Tunisia. It is classified as the second leading cause of cancer-related mortality on a global scale. The carcinogenesis process is multifactorial, mainly involving genetic and environmental factors. Recent studies in various countries suggest that Cryptosporidium, an emerging intestinal protozoan, may be associated with this cancer pathology.

Objective: This study aimed to estimate the prevalence of Cryptosporidium in intestinal biopsies from Tunisian CRC patients.

Materials and methods: Formalin-fixed, paraffin-embedded intestinal biopsies from 39 Tunisian CRC patients were studied. After DNA extraction, Cryptosporidium was detected using two PCR techniques, one TaqMan targeting 18S rRNA and the other HRM (High Resolution Melt) targeting the DHFR (Dihydrofolate reductase) gene. PCR-HRM was also used to identify Cryptosporidium species.

Results: The protozoan parasite was detected in five biopsies from CRC patients by at least one PCR (three by the TaqMan technique and three by the HRM technique, including one by both techniques). The overall Cryptosporidium infection rate was 13% (5/39). This prevalence was well above those reported in the few studies carried out in the Tunisian population. Cryptosporidium parvum was identified in three of the five infected biopsies. This species is the most implicated in intestinal carcinogenesis.

Conclusion: The high prevalence (13%) of Cryptosporidium infection observed in Tunisian CRC patients correlates with data from similar series and would suggest a potential association between this protozoan and CRC. Further studies on more numerous and more suitable biological samples, such as stool and fresh intestinal biopsies, would enable this hypothesis to be investigated in greater depth.