Histophotometric quantification of the field effect and the extended field effect of tumors.

Histophotometric investigations have been made on samples of human skin. Fresh frozen serial sections were fixed and stained for either reactive protein thiols (PSHr) or total reactive protein sulphur (TRPS) using modifications of the DDD-Fast blue B-method. In addition, total protein thiols (PSHt) were stained with the Mercurochromcyanide-method, and proteins were stained using a modified amido-black procedure. Significant differences were found between the different tumours investigated and normal tissue, and also between apparently normal tissue adjacent to the tumours and normal tissue from patients without tumour. To reveal such tumour-related changes of apparently normal tissue, termed the field effect of tumours, a double quotient had to be calculated from the PSHr-and TRPS-values determined from both epithelium (epidermis) and connective tissue. In addition, abdominal skin was investigated from patients without tumour and patients with tumours of the female genital tract, liver or breast. With the aid of the double quotient procedure, highly significant differences were found between normal abdominal skin of patients without tumours versus similar samples taken from patients with tumours. The tumour-related changes found with abdominal skin distant from the tumours have been termed the extended field effect of tumours. These general tumour-related changes, independent of the size, state or degree of malignancy of the distant tumour, could be shown to be due to changes in abdominal dermis.