Cancer prevention

Prostate carcinogenesis in N -methyl- N -nitrosourea (NMU)-testosterone-treated rats fed tomato powder, lycopene, or energy-restricted diets. Boileau, T. W. -M. et al. J. Natl Cancer Inst. 95, 1578–1586 (2003)

Increased consumption of tomato products is known to reduce the risk of prostate cancer. Lycopene — the principal carotenoid in tomatoes — is thought to be the active component that produces the antitumour effects. Boileau et al. show that consumption of tomato powder, but not lycopene alone, inhibits prostate carcinogenesis in rats, indicating that other phytochemicals in tomatoes are required to prevent tumour formation.

Prostate cancer

Pten dose dictates cancer progression in the prostate. Trotman, L. C. et al. PLoS Biology, 27 Oct 2003 (doi: 10.1371/journal.pbio.0000059)

Loss of one allele of the tumour-suppressor gene Pten is common in prostate tumours, so the authors studied the effects of Pten dose variations on cancer progression in mice. They found that the levels and extent of Pten inactivation dictates prostate cancer incidence, progression, latency and pathogenesis. So, Pten dose is a key determinant in cancer progression.

Gene therapy

LMO2 -associated clonal T cell proliferation in two patients after gene therapy for SCID-X1. Hacein-Bey-Abina, S. et al. Science 302, 415–419 (2003)

X-linked severe-combined immunodeficiency (SCID-X1) has been successfully corrected in 9 out of 10 patients by retroviral transfer of the γc gene into bone-marrow progenitor cells. However, two patients later developed leukaemia-like syndromes due to uncontrolled proliferation of mature T cells. Hacein-Bey-Abina et al. report that the syndromes were caused by activation of the LMO2 oncogene, following insertion of the γc gene into the LMO2 promoter.

Epidemiology

Breast and ovarian cancer risks due to inherited mutations in BRCA1 and BRCA2. King, M. -C., Marks, J. H. & Mandell, J. B. Science 302, 643–646 (2003)

Germ-line BRCA1 and BRCA2 mutations account for most cases of familial breast and ovarian cancer. As a high population frequency of three ancient BRCA1 and BRCA2 mutations is found in Ashkenazi Jewish women, King et al. studied breast and ovarian cancer risks in a cohort of these women. A key finding from this study is that non-genetic factors, such as obesity and lack of exercise, seem to significantly influence the penetrance of these already highly penetrant mutations, as risk is higher for women born after 1940 than before 1940.