Prospective evaluation of a novel approach for the use of a quantitative galactose oxidase-Schiff reaction in ductal fluid samples from women with breast carcinoma

BACKGROUND. The galactose oxidase-Schiff reaction (GOS) yields positive findings in a number of malignant solid tumors. The goals of the current study were to develop a novel technique for quantifying GOS reactivity in nipple aspirate fluid (NAF) samples from women with invasive breast carcinoma and to assess the clinical utility of the technique in this setting. METHODS. Patients with biopsy-proven unilateral invasive breast carcinoma were eligible for study entry. Before definitive surgery, NAF samples were obtained from healthy breast tissue and malignant breast tissue from 23 women with breast carcinoma. Under blind conditions with respect to clinical data, 10 μL NAF samples were applied to a glass fiber membrane and incubated with 100 μL galactose oxidase and 1 mL Schiff reagent. The stain was developed and the color reaction quantitated by measuring hue (shade) and chroma (intensity) using a spectrophotometer. RESULTS. GOS reactivity was quantitated using two color parameters, hue and chroma. Because chroma varies with concentration, this measurement was adjusted for the concentration of NAF in each sample. After adjustment for NAF concentration, chroma was found to be statistically significantly different in the affected breast tissue sample and the healthy contralateral internal control sample (P = 0.001). CONCLUSIONS. A quantitative measure of GOS reactivity based on spectrophotometric measurement of intensity of color has been developed and was found to be significantly different in the affected breast compared with the unaffected breast in the current population of patients with breast carcinoma. The preliminary results support further exploration of this novel quantitative test in patients with breast carcinoma.