Escherichia coli and Streptococcus bovis in colon cancer
Several bacteria have now been linked to chronic infections of the colon and an increased risk of colon cancer. These include Escherichia coli (McCoy and Mason suggested this in 1951) and in more recent studies Streptococcus bovis. Colon cancer incidence that may be associated with S. bovis has been estimated at 18% to 62% (Zarkin 1990).
Infection in oral squamous cell carcinomas
Over 90% of oral cancers are oral squamous cell carcinomas (OSCC). These have one of the lowest survival rates (based on 5-year survival statistics), with no noticeable improvements in the last few decades (Canto 2002).
In a recent study (2005) Mager et al used DNA identification of oral flora to test for 40 microbial species. Capnocytophaga gingivalis, Prevotella melaninogenica and Streptococcus mitis were elevated in the saliva of patients with OSCC. When testing the presence of these three species as diagnostic markers, the authors found that their presence could predict 80% of cancer cases and absence could predict 83% of controls.
The sensitivity of nested PCR as compared to a kit method PCR (DNA probe) is significantly greater and allows detection of one organism per mL of blood. At Australian Biologics in Sydney we carried out a small scale PCR study of breast cancer patients choosing only patients who had not had conventional treatments such chemotherapy or radiotherapy. This was to eliminate any question of possible bacterial presence being due to immune suppression as a result of treatment.
PCR results
Eleven women were tested with varying types of breast cancer for the presence of the Mycoplasma species, the Chlamydia species and for Streptococci. The results were as follows:
Case Study 1
Male, 59, past history of prostate cancer, currently diagnosed with follicular lymphoma with multiple nodes. Nested PCR was carried out on the following sample types with the following results.
Lymphoma tissue: M. fermentans + M hominis +
Blood: M. fermentans + M hominis +
Bone marrow: M. fermentans +
Treatment: Klacid [R] (clarithromycin) and
Augmentin [R] (amoxycillin/clavulanate).
Response: In less than 14 days one tumour disappeared another diminished by half.
Case Study 2
Male 63, diagnosed with prostate cancer. Nested PCR was carried out on the following sample types with the following results.
Swab (urethral): Mycoplasma fermentans +
Urine: Mycoplasma fermentans +
Semen: Mycoplasma hominis +
Treatment: Klacid [R] and Augmentin [R].
Response: PSA increased from 5.1 to 5.8. Free/total PSA increased from 3% to 12%.