Agents associated with colorectal cancer 2

CHAPTER ASSOCIATION STUDY 4.1 Background Bacteria are in a unique position to mediate between the host and its external environment because they naturally colonise all external surfaces. The gut bacterial flora has an overwhelmingly beneficial role in assisting digestion and in detoxifying ingested compounds of exogenous origin [Hill MJ, 1995; Huycke MM and Gaskins HR, 2004]. However, there are also situations where an introduction of pathogenic bacteria can cause bacterial infection, probably can also produce carcinogens and in some instances, lead to colon cancer development in the host [Oshima M et al.,1996; Hubbard AL et al., 1998; Swidsinski A et al., 1998; Newman JV et al., 2001; Huycke MM and Gaskins HR, 2004; Alistair J L, 2005; Laurent C et al., 2007 ]. This development, however, may not be solely due to the bacteria, as a normal healthy host is known to be equipped with the healthy immune surveillance system to ward off such offensive attacks. But nevertheless, as the first step, to be able to gain an insight into the role of bacteria in cancer cell formation, one needs to be able to correlate histopathology with quantity and depth of bacteria’s presence in order to evaluate their role in gastrointestinal infection and cancer. 64 The preliminary study had resulted in the identification of unique DNA sequence (81B) for E.coli and the isolation and identification of E.coli with interesting determinants (Tia, HRA1 and CNF1). By amplifying the bacterial sequence presence in total genomic DNA of colon tissue collected from normal and cancer subjects, we had also found a significant difference (p[...]... nucleus of mucosal cells of the tumor 92 (p . those of subjects with polyps (22 /22 , 100%; Table 4.7). HRA1-positive bacteria were found to be more prevalent in subjects with polyps (p<0.05; 9 /22 , 40.9%; Table 4.7) and in cancer subjects. colonoscopic findings and past history: 1) 41 Patients with colorectal cancer 2) 25 Patients with colorectal polyps 3) 41 Patients with no endoscopic abnormalities 4.3.4 Collection of specimens. for 2 min; (ii) 10 cycles of 30 sec at 94C, 30 sec at 58C, 60 sec at 72 C, and then (iii) 15 cycles of 30 sec at 92 C, 30 sec at 55C, 60 sec at 72 C with an auto extension of 5 sec at 72 C