The immune system and breast carcinoma, implications of dietary and other associated factors

by Hoption Cann, Stephen Arthur

Introduction: A review of animal and human studies demonstrates that the immune system is a major factor in both the enhancement and inhibition of malignant tumour growth. Macrophages, one of the most durable and versatile immune cells, may be key to this immune duality. Macrophages have been observed in particuIariy high concentrations in and around breast tumours. It has been suggested that these cells generaily aid tumour growth, unless activated by an acute infections, imrnunomoduIatorsor other means. Stuc$ L Using immun0 histochernistry and cornputer-aided image analysis, rnacrop hage concentrations in and around breast tumours were examined. Other pathoIogical tissues were also examined for comparative purposes. Macrophage density was found to correlate positively with the Modified Bloom Richardson (MBR) grade (r = 0.41) and MBR subscore (r = 0.44), suggesting that macrophage concentrations increase as tumours become more aggressive. Similar infiltrations of macrophages were observed in lung, prostate and hyperplastic thyroid tissues; although in these latter tissues, macrophages were generaily confined to the tumour periphery. Stud) II: Iodine has been shown to play many roles in normal human physiology. In addition to its incorporation into thyroid hormones, iodine also has antibiotic and antiturnour properties. EpidernioIogicai studies of iodine in breast cancer have not been conducted. In this pilot case-control study, whole blood levels of 10 trace elements (Br, Cr, Fe, 1, Mb, Mg, Mn, Se, V, and Zn) and their association with breast cancer was investigated. Other general, medical and dietary characteristics were examined as well. In comparison with iodine levels in Japm, iodine levels in the population under study were considerably lower, with a mean of 28.4 pg/i and a range of 19-35 pg/l. In the univariate Iogistic regression analysis, a number of significant associations with breast cancer were observed. A high education status (OR = 0.31) and high iron status (OR = 0.15) were associated with reduced risks, whereas previous hysterectomy or ovariectomy was associated with an increased nsk of breast cmcer (OR = 3.64). In the adjusted multivariate analysis, a high iron status remained associated with a reduced risk (OR = 0.01) and a history of breast pain with an increased risk (OR = 11 -25).