COMPARISON OF IMMUNOHISTOCHEMICAL AND BIO CHEMICAL DETERMINATION OF ESTROGEN-RECEPTORS IN MAMMARY-CARCINOMA

Immunohistochemical (IH) assessment of nuclear estrogen receptor has b een considered an alternative method to conventional biochemical assay . The present work intends to compare specificity and sensitivity of I H and biochemical technique to assess nuclear estrogen receptor in for malin-fixed and paraffin-embedded mammary carcinoma samples. IH positi ve reaction was defined as 14% or more nuclear staining in 100 cells c ounted under high magnification (400x). Biochemical assay was consider ed positive over 10 fmol/mg of protein. 66 cases were collected with a mean age of 55.6 years and a mean tumor size of 25.2 mm. Histological ly, 62 cases were ductal carcinomas, 2 lobular carcinomas, and 2 medul lary carcinomas. Biochemical assay for estrogen receptor was positive in 35 cases (63%) and IH in 40 cases (71%). The present results show t hat IH assessment of estrogen receptor is highly specific and sensitiv e. Estrogen receptor present in non-tumor cells and blood vessels wall s may disclose false positive biochemical results and false negative r esult is the tumor mass is small or there are isolated tumor cells. IH assessment of estrogen receptor can be performed in small samples, in cluding in situ lesions. The method is fast, reliable, and of lower co st. IH may be considered the method of choice in cases with insufficie nt sample for biochemical assay and/or in tumors containing scant cell s.