Cyclin E overexpression and amplification in human tumours

Cyclin E amplification and overexpression have recently been described in several tumour types. However, many tumour entities have never been examined for cyclin E alterations. Numerous and time-consuming experiments were previously required to determine the significance of potential oncogenes across different tumour types. To overcome this problem, tissue microarrays (TMAs) consisting of 3670 primary tumours from 128 different tumour types, 709 metastases, and 354 normal tissues were generated. Cyclin E alterations were then analysed by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). Cyclin E gene amplification was observed in 15 different tumour types and subtypes, ie rhabdomyosarcoma, urinary bladder cancer (three subtypes), ovarian cancer (two subtypes), malignant fibrous histiocytoma, adenocarcinoma of the small intestine, medullary breast cancer, gall bladder adenocarcinoma, phaeochromocytoma, gastric adenocarcinoma, squamous cell carcinoma of the uterine cervix, colonic adenocarcinoma, and endometrial carcinoma. Cyclin E protein accumulation was found in 48 different tumour types. The use of TMA technology has enabled us to expand considerably our knowledge of cyclin E alterations in human tumours. The occurrence of amplification and overexpression in many different tumour types suggests that cyclin E plays an important role in tumour biology.