Role of the tumour necrosis family ligand APRIL in solid tumour development: Retrospective studies in bladder, ovarian and head and neck carcinomas

A proliferation inducing ligand (APRIL) from the tumour necrosis family (TNF) promotes the natural development of solid tumours in pre-clinical models. Here, we studied the role of APRIL in patients with urothelial bladder, epithelial surface ovarian, and head and neck squamous carcinomas. By using immunohistochemistry, we revealed an upregulation of APRIL expression in lesions from a significant subset of patients compared to corresponding healthy tissues. APRIL upregulation was not due to autocrine production by tumour cells, but rather originated from infiltration of APRIL-producing neutrophils. Heparan sulphate proteoglycan (HSPG) efficiently concentrated secreted APRIL in lesions. Despite this retention, in situ APRIL upregulation did not significantly alter disease-free and overall survivals of carcinoma patients in retrospective studies. This indicates that APRIL is not potent enough to promote the development of solid tumour cells under the pressure of chemotherapy.