Carmina Villariba-Tolentino1,2,3, Ana Maria Cariño1,2,4, Kin Israel Notarte5, Imee Macaranas5, Allan Fellizar1,2,6, Rock Christian Tomas7, Lara Mae Angeles5,8, Lorenzo Abanilla9, Antonio Lim9, Ma Kristina Carmela Aguilar1,2, Pia Marie Albano10,11,12. 1. The Graduate School, University of Santo Tomas, 1015, Manila, Philippines. 2. Research Center for the Natural and Applied Sciences, University of Santo Tomas, 1015, Manila, Philippines. 3. Manuel S. Enverga University Foundation, 4301, Lucena, Philippines. 4. Quirino State University, 3401, Diffun, Philippines. 5. Faculty of Medicine and Surgery, University of Santo Tomas, 1015, Manila, Philippines. 6. Mariano Marcos Memorial Hospital and Medical Center, 2906, Batac, Philippines. 7. University of the Philippines Los Baños, 4031, Los Baños, Laguna, Philippines. 8. University of Santo Tomas Hospital, 1015, Manila, Philippines. 9. Divine Word Hospital, 6500, Tacloban, Philippines. 10. The Graduate School, University of Santo Tomas, 1015, Manila, Philippines. psalbano@ust.edu.ph. 11. Research Center for the Natural and Applied Sciences, University of Santo Tomas, 1015, Manila, Philippines. psalbano@ust.edu.ph. 12. College of Science, University of Santo Tomas, Manila, Philippines. psalbano@ust.edu.ph.
Abstract
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.
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.
Authors: Leonardo A Guevarra; Andrea Claudine F Afable; Patricia Joyce O Belza; Karen Joy S Dy; Scott Justin Q Lee; Teresa T Sy-Ortin; Pia Marie S P Albano Journal: Infect Agent Cancer Date: 2018-04-02 Impact factor: 2.965