International journal of cancer. Journal international du cancer
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Review Multicenter Study Comparative Study
CYP17 polymorphisms in relation to risks of prostate cancer and benign prostatic hyperplasia: a population-based study in China.
Because androgens likely play a key role in prostate growth and prostate cancer development, variants of genes involved in androgen biosynthesis may be related to prostate cancer risk. The enzyme P450c17alpha, encoded by the CYP17 gene, catalyzes the conversion of progesterone and pregnenolone into precursors of potent androgens. In the 5' promoter region of the CYP17 gene, a T (A1 allele) to C substitution (A2 allele) has been hypothesized to increase CYP17 gene expression, resulting in higher levels of androgens. ⋯ A similar association of the A1/A1 genotype with BPH was suggested. We found no associations of CYP17 genotypes with serum sex hormone levels or other biomarkers after correction for multiple comparisons. Large population-based studies are needed to clarify whether CYP17 plays a role in prostate cancer risk and whether genotype effects vary in different racial/ethnic and other subgroups.
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Comparative Study
Smoking and liver cancer in China: case-control comparison of 36,000 liver cancer deaths vs. 17,000 cirrhosis deaths.
Liver cancer and liver cirrhosis are common causes of death in China, where chronic lifelong hepatitis B infection is a major cause of both diseases. To help determine whether smoking is a cofactor for the development of liver cancer, we ascertained retrospectively the smoking habits of 36,000 adults who had died from liver cancer (cases) and 17,000 who had died from cirrhosis (controls) in 24 Chinese cities and 74 rural counties. Calculations of the smoker vs. nonsmoker risk ratios (RR) for liver cancer mortality were standardised for age and locality. ⋯ Smoking was also associated with a significant excess of liver cancer death in women (RR 1.17, 95% CI 1.06-1.29, 2p=0.003; attributable fraction 3%), but fewer women (17%) than men (62%) were smokers, and their cigarette consumption per smoker was lower. Among women who smoked only cigarettes, there was a significantly greater hazard among those who smoked at least 20/day (mean 22/day: RR=1.45, 95% CI 1.18-1.79) than among those who smoked fewer (mean 8/day: RR=1.09, 95% CI 0.94-1.25). These associations indicate that tobacco is currently responsible for about 50,000 liver cancer deaths each year in China, chiefly among men with chronic HBV infection.
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The specific activation of the immune system to control cancer growth in vivo has been a long-standing goal in cancer immunology and medical oncology. The identification of tumor-associated antigens has provided the basis for new concepts in antigen-specific immunotherapy. The first clinical trials on cancer vaccines were designed to evaluate the toxicity and objectively measurable immunologic effects in relation to clinical developments mostly in patients with metastatic disease. ⋯ Standardized assay systems to evaluate the immunologic effects of cancer vaccines have been established. Clinical developments during and after vaccination were followed in relation to vaccine-induced immune responses. Prognostic tumor features, i.e., homogeneity of tumor antigen and MHC class I/II expression and intratumoral cellular infiltrates, have been identified that may help to select patients who are more likely to benefit from antigen-specific cancer vaccines in the future.
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Comparative Study
Antitumor and antimetastatic activities of Angelica keiskei roots, part 1: Isolation of an active substance, xanthoangelol.
The roots of Angelica keiskei Koizumi have traditionally been used as a health food, with diuretic, laxative, analeptic and galactagogic effects. It has been thought that the roots and leaves of A. keiskei have preventive effects against coronary heart disease, hypertension and cancer. In the present study, we examined the antitumor and antimetastatic activities of various fractions isolated from a 50% ethanol extract of A. keiskei roots. ⋯ Xanthoangelol inhibited tumor-induced neovascularization (in vivo) at doses of 10 and 20 mg per kg, and it inhibited the Matrigel-induced formation of capillary-like tubes by HUVECs at concentrations of 1-100 microM. Furthermore, xanthoangelol inhibited the binding of VEGF to HUVECs at concentrations of 1-100 microM. These results indicate that the antitumor and/or antimetastatic activities of xanthoangelol may be due to inhibition of DNA synthesis in LLC cells and of tumor-induced neovascularization through inhibition of the formation of capillary-like tubes by vascular endothelial cells and inhibition of the binding of VEGF to vascular endothelial cells.
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Coexpression for c-Kit receptor and its ligand stem cell factor (SCF) has been described in neuroblastoma (NB) cell lines and tumors, suggesting the existence of an autocrine loop modulating tumor growth. We evaluated c-Kit and SCF expression by immunohistochemistry in a series of 75 primary newly diagnosed neuroblastic tumors. Immunostaining for c-Kit was found in 10/75 and for SCF in 17/75, with 5/10 c-Kit-positive tumors also expressing SCF. ⋯ In addition, c-Kit-positive cell lines SK-N-BE2(c) and HTLA230, grown in SCF only, remained sensitive (40 and 70% of growth inhibition, respectively), while, in the same conditions, proliferation of the c-Kit-negative cell line GI-CA-N was not affected. Immunoprecipitation of c-Kit from cell lysates of SK-N-BE2(c) and HTLA230 cells grown in SCF and subsequent western blot analysis of the immunoprecipitates revealed a sharp decrease of c-Kit phosphorylation after STI-571 treatment. These data demonstrate that both c-Kit and SCF are preferentially expressed in vivo in the most aggressive neuroblastic tumors and that their signaling is active in promoting in vitro NB cell proliferation that can be selectively inhibited by treatment with STI-571.