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pks+ Escherichia coli more prevalent in benign than malignant colorectal tumors
Carmina Villariba-Tolentino1,2,3, Ana Maria Cariño1,2,4, Kin Israel Notarte5
1The Graduate School, University of Santo Tomas, 1015, Manila, Philippines.
Background:
Some E. coli strains that synthesize the toxin colibactin within the 54-kb pks island are being implicated in colorectal cancer (CRC) development. Here, the prevalence of pks+ E. coli in malignant and benign colorectal tumors obtained from selected Filipino patients was compared to determine the association of pks+ E. coli with CRC in this population.
Methods And Results:
A realtime qPCR protocol was developed to quantify uidA, clbB, clbN, and clbA genes in formalin fixed paraffin embedded colorectal tissues. The number of malignant tumors (44/62; 71%) positive for the uidA gene was not significantly different (p = 0.3428) from benign (38/62; 61%) tumors. Significantly higher number of benign samples (p < 0.05) were positive for all three colibactin genes (clbB, clbN, and clbA) compared with malignant samples. There was also higher prevalence of pks+ E. coli among older females and in tissue samples taken from the rectum.
Conclusion:
Hence, pks+ E. coli may not be associated with CRC development among Filipinos.
