Summary We have investigated the oestrogen receptor (ER) status of 20 cervical adenocarcinomas by immunocytochemistry for ER protein and non-isotopic in situ hybridisation for ER mRNA. Both methods, which are applicable to paraffin sections, were developed and validated in breast carcinomas with known ER content. Six cervical adenocarcinomas contained immunocytochemically demonstrable ER protein; all contained ER mRNA, but staining was less intense in poorly differentiated areas of four tumours. This disparity between protein and mRNA detection needs further investigation as does the possibility that oestrogens may play a role in the pathogenesis of cervical adenocarcinoma.Adenocarcinoma of the cervix is a relatively rare tumour which is increasing in incidence among young women (Peters et al., 1986;Schwartz & Weiss, 1986;Chilvers et al., 1987). Little is known of its aetiology and pathogenesis.The cervix, like the breast, is a target tissue for oestrogens and progesterone. This is shown by menstrual cycle related alterations in the quality of cervical mucus (Wakefield & Wells, 1985), and the demonstration of oestrogen and progesterone receptors in the normal cervix (Kupryjanczyk & M6ller, 1988;Cano et al., 1990;Nonogaki et al., 1990). While the clinical and biological significance of oestrogen receptor status in breast carcinoma has been extensively studied, very little factual information is available on the presence of oestrogen receptors in cervical adenocarcinoma.Having validated our methodology in a series of breast carcinomas with known ER protein content, we studied ER mRNA and protein content of 20 cervical adenocarcinomas.
Materials and methods
ImmunocytochemistryAll tissues were fixed in 10% formol saline and embedded in paraffin wax. Five ym sections were dewaxed, rehydrated and immunostained using a modification of an avidinbiotin-peroxidase complex technique for detection of ER (Andersen et al., 1986;Cheng et al., 1988). After blocking endogenous peroxidase activity the sections were digested at 37°C in a 0.02% Pronase E (Sigma, P6911) solution for 20-30min. The washed slides were incubated with normal swine serum, followed by application of anti-ER monoclonal antibody (H222) or control antibody (rat IgG) overnight at room temperature. After washing, the slides were incubated at room temperature with biotinylated sheep anti-rat IgG (Amersham) for 30 min, and avidin-biotin complex (Dako) for 1 h. The reaction was developed with diaminobenzidine. The staining was intensified by immersing the slides for 10 min in 0.5% CuSO4 in 0.85% NaCl. Counterstaining was performed with 1% methylgreen.In situ hybridisation A 24 base cDNA oligonucleotide probe (5' CTC CAG CTC GTT CCC TTG GAT CTG 3') complementary to human ER mRNA coding for amino acids 17-24 was synthesised to our specifications (British Bio-technology Ltd., Abingdon, (Green et al., 1986;Pelletier et al., 1988;Ponglikitmongkol et al., 1988;Graham et al., 1991). The probe was labelled at the 5' end with digoxigenin-l 1-UTP and purified by HPLC. A 2...