Introduction

In 2015, an estimated number of 8430 new cases of germ cell tumour (GCT) will be diagnosed in the USA.1 Although GCTs show a high sensitivity to cisplatin-based chemotherapy, 10%–15% of patients fail first-line chemotherapy and 3%–5% of all patients with GCT will eventually die of their disease.2 Despite a response rate above 95% to cisplatin-based chemotherapy, the search for new treatment strategies remains worthwhile in accordance to reduce treatment toxicity and offer therapeutic options in non-responding patients.3–5 Various tumours have been described to express L1 cell adhesion molecule (L1-CAM) including lung carcinoma, gliomas, melanoma, renal, ovarian, endometrial and colon carcinoma.6 L1-CAM is associated with tumour cell dissemination via the regulation of prometastatic MMP-2 and MMP-9 in solid and non-solid tumours7 as well as in brain metastases.8 L1-CAM is involved in epithelial-to-mesenchymal transition.9 In various malignancies, there is evidence showing that the expression of L1-CAM is associated with a subset of highly aggressive tumours with adverse clinical outcome and might serve as a therapeutic target.10 We aimed to investigate the expression of L1-CAM in the different GCT subtypes.