The Inside Edge (Nov 2009)
US researchers say they have discovered a metabolic deficiency in pancreatic cancer cells that can be used to slow its progress. They found that an enzyme needed to synthesise the amino acid arginine was lacking in 87 per cent of the 47 tumour specimens examined, suggesting that the majority of pancreatic cancers need to obtain arginine for cell growth because they cannot synthesise it. Further studies using cell cultures and mice demonstrated that pancreatic cancer cell proliferation could be significantly reduced by depleting arginine levels. (Bowles TL, Kim R, Galante J et al. Int J Cancer 2008;123:1950-5)
An association between allergies and cancer has long been suspected. Researchers in the US re-examined almost 650 studies from the past 50 years and found that inverse allergy/cancer associations were far more common with cancers of organ systems that come into contact with the external environment, such as the skin. Only allergies associated with tissue directly exposed to environmental assault, such as eczema or food allergy, had inverse relationships to cancers. The researchers suggest allergy symptoms may protect against cancer by expelling foreign particles, which may be carcinogenic or carry carcinogens. (Sherman PW, Holland E, Sherman JS. Q Rev Biol 2008;83(4):339-62)
The prostate cancer gene 3 (PCA3) assay appears to be promising as a diagnostic aid. A prospective, multicentre study in Europe enrolled 463 men with one or two negative biopsies who were scheduled for repeat biopsy. Positive repeat biopsy rate was 28 per cent and the higher the PCA3 score, the greater the probability of a positive repeat biopsy. Furthermore, PCA3 score was superior to percentage free prostate specific antigen in predicting repeat prostate biopsy outcome. PCA3 score was also significantly higher in men with high-grade prostate intraepithelial neoplasia than in those without. The researchers say PCA3 score may indicate the clinical stage and significance of prostate cancer. (Haese A, de la Taille A, van Poppel H et al. Eur Urol 2008;54:1081-8)
Most patients are not given clear information on the survival gain of palliative chemotherapy, a UK study has shown. Nine oncologists and 37 patients with advanced non- small cell lung cancer (n = 12), pancreatic cancer (n = 13) and colorectal cancer (n = 12) took part in the study. Consultations were observed, recorded, transcribed and analysed. The researchers found that information given to patients about survival benefit included numerical data ('about four weeks'), an idea of timescale ('a few months extra'), vague references ('buy you some time'), or no mention at all. In 26 out of 37 consultations, discussion of survival benefit was vague or non-existent. (Audrey S, Abel J, Blazeby JM, Falk S. BMJ 2008;337:a752)
Serum microRNAs (miRNAs) are naturally occurring, small, non-coding RNAs linked with cancer, which could be a useful diagnostic tool. Recent research was unable to discount contamination, but one study has characterised the whole blood miRNA profiles of healthy subjects and patients with lung cancer, colorectal cancer and diabetes, ruling out contamination. The researchers say the serum miRNA expression profiles constitute 'fingerprints' for cancer and disease. This could improve diagnosis, cancer classification and prognosis estimation. (Chen X, Ba Y, Ma L et al. Cell Res 2008;18:997-1006)
Optimism may protect against breast cancer. Researchers in Israel have found that exposure to more than one adverse life event, such as the loss of a parent or spouse, raised breast cancer risk 62 per cent, while a general feeling of happiness and optimism reduced risk by 25 per cent. The case-control study involved 622 women aged below 45 years, 255 with breast cancer and 367 healthy controls. The researchers concluded that young women who have been exposed to a number of adverse life events should be considered a risk group for breast cancer and treated accordingly. (Peled R, Carmil D, Siboni-Samocha O, Shoham-Vardi I. BMC Cancer 2008; 8: 245 www.biomedcentral.com/1471-2407/8/245)
Originally published in the November 2009 edition of MIMS Oncology & Palliative Care.