فهرست نشریات علمی دسترسی آزاد ایران

Introduction : Colorectal cancer (CRC) is a major global health issue. The gut microbiota has become an important factor in CRC development, with increased focus on microbes such as Lactobacillus plantarum . This study aimed to examine the presence and relative abundance ( GAPDH -normalised copy number) of L. plantarum in colorectal tissues using a qPCR approach. Materials & Methods : DNA was extracted from formalin-fixed paraffin-embedded (FFPE) tissues from three groups: tumour tissues from CRC patients (n = 50), matched adjacent normal tissues (n = 50), and normal tissues from individuals without CRC (n = 30). Species-specific primers targeting the groEL gene were used to measure L. plantarum , normalised against human GAPDH . Statistical analyses compared occurrence and levels across groups and assessed associations with age and sex. Results : Although bacterial load did not vary significantly across tumour, Adjacent, and Normal tissues, detection frequency was higher in tumour tissues (p = 0.0459). L. plantarum was also detected more often in individuals aged ≥60 (p = 0.0024). Subgroup analysis revealed higher loads in Normal tissues of older adults and females and lower abundance in Adjacent tissues of females. Conclusion : L. plantarum was detected more frequently in tumour tissues despite consistent bacterial loads, indicating possible persistence rather than growth. These findings highlight age-, sex-, and tissue-specific colonisation patterns and emphasise the need for further research on the tumour-associated ecology of beneficial microbes.