title: HMGA2 expression distinguishes between different types of postpubertal testicular germ cell tumour.
abstract: The group of postpubertal testicular germ cell tumours encompasses lesions with highly diverse differentiation - seminomas, embryonal carcinomas, yolk sac tumours, teratomas and choriocarcinomas. Heterogeneous differentiation is often present within individual tumours and the correct identification of the components is of clinical relevance. HMGA2 re-expression has been reported in many tumours, including testicular germ cell tumours. This is the first study investigating HMGA2 expression in a representative group of testicular germ cell tumours with the highly sensitive method of quantitative real-time PCR as well as with immunohistochemistry. The expression of HMGA2 and HPRT was measured using quantitative real-time PCR in 59 postpubertal testicular germ cell tumours. Thirty specimens contained only one type of tumour and 29 were mixed neoplasms. With the exception of choriocarcinomas, at least two pure specimens from each subgroup of testicular germ cell tumour were included. In order to validate the quantitative real-time PCR data and gather information about the localisation of the protein, additional immunohistochemical analysis with an antibody specific for HMGA2 was performed in 23 cases. Expression of HMGA2 in testicular germ cell tumours depended on the histological differentiation. Seminomas and embryonal carcinomas showed no or very little expression, whereas yolk sac tumours strongly expressed HMGA2 at the transcriptome as well as the protein level. In teratomas, the expression varied and in choriocarcinomas the expression was moderate. In part, these results contradict data from previous studies but HMGA2 seems to represent a novel marker to assist pathological subtyping of testicular germ cell tumours. The results indicate a critical role in yolk sac tumours and some forms of teratoma.
authors: Center for Human Genetics University of Bremen Bremen Germany.
authors: Lars
authors: L
authors: Kloth
authors: Center for Human Genetics University of Bremen Bremen Germany.
authors: Andrea
authors: A
authors: Gottlieb
authors: Institute for Pathology, Elbe Clinic Stade-Buxtehude Buxtehude Germany.
authors: Burkhard
authors: B
authors: Helmke
authors: Institute of Statistics, University of Bremen Bremen Germany.
authors: Werner
authors: W
authors: Wosniok
authors: Department of Pathology Albertinen Hospital Hamburg Germany.
authors: Thomas
authors: T
authors: Löning
authors: Department of Pathology Clinical Centre Bremen-Mitte Bremen Germany.
authors: Käte
authors: K
authors: Burchardt
authors: Center for Human Genetics University of Bremen Bremen Germany.
authors: Gazanfer
authors: G
authors: Belge
authors: Leibniz Institute for Prevention Research and Epidemiology - BIPS GmbH Bremen Germany.
authors: Kathrin
authors: K
authors: Günther
authors: Center for Human GeneticsUniversity of Bremen BremenGermany; Institute for Medical Genetics, University of Rostock, University Medicine RostockGermany.
authors: Jörn
authors: J
authors: Bullerdiek
keywords: HMGA2; biomarker; choriocarcinoma; embryonal carcinoma; immunohistochemistry; qRT‐PCR; seminoma; teratoma; testicular germ cell tumour; yolk sac tumour