Cancer treatment: the critical genetic factors

March 25, 2008

DEGUID=%7bBF69BD89-1F82-4852-B39B-EA6A2CC271AA%7d & NRORIGINALURL=%2fnewsletter%2f\

2008%2f0325_one-cup-of-green-tea-per-day-cuts-ovarian-cancer-risk%2ehtm & NRCACHEH\

INT=NoModifyGuest>

Cancer treatment: the critical factors

The family of proteins known as Ras plays a central role in the

regulation of cell growth. It fulfills this fundamental role by

integrating the regulatory signals that govern the cell cycle and

proliferation.

Defects in the Ras-Raf pathway can result in cancerous growth. Mutant

Ras genes were among the first oncogenes identified for their ability to

transform cells to a cancerous phenotype, that is, a cell observably

altered because of distorted gene expression. Mutations in one of three

genes (H, N, or K-Ras) encoding Ras proteins are associated with

upregulated cell proliferation and are found in an estimated 30-40% of

all human cancers. The highest incidences of Ras mutations are found in

cancers of the pancreas (80%), colon (50%), thyroid (50%), lung (40%),

liver (30%), melanoma (30%), and myeloid leukemia (30%) ( Duursma et al.

2003; Minamoto et al. 2000 ; Vachtenheim 1997; Bartram 1988 ; Bos 1989;

Minamoto et al. 2000 ).

According to information in Scientific American, the differences between

oncogenes and normal genes are slight. The mutant protein that an

oncogene ultimately creates may differ from the healthy version by only

a single amino acid, but this subtle variation can radically alter the

protein's functionality.

Researchers at Rutgers University investigated the ability of different

green and black tea polyphenols to inhibit H-Ras oncogenes. The Rutgers

team found that all the major polyphenols contained in green and black

tea except epicatechin showed strong inhibition of cell growth (Chung et

al. 1999). Texas A & M University also found that fish oil decreased

colonic Ras membrane localization and reduced tumor formation in rats.

In view of the central role of oncogenic Ras in the development of colon

cancer, the finding that omega-3 fatty acids modulate Ras activation

likely explains why dietary fish oil protects against colon cancer

(Collett et al. 2001).

Recommended Posts