Characterisation of Walker 256 breast carcinoma cells from two tumour cell banks as assessed using two models of secondary brain tumours

In this study internal carotid artery injection and direct cerebral inoculation models of secondary brain tumours were used to determine the tumorigenicity of Walker 256 cells obtained from two cell banks, the American Type Culture Collection (ATCC), and the Cell Resource Centre for Medical Research at Tohoku University (CRCTU).Tumour incidence and volume, plus immunoreactivity to albumin, IBA1 and GFAP, were used as indicators of tumorigenicity and tumour interaction with the host brain microenvironment. CRCTU Walker 256 cells showed greater incidence, larger tumour volume, pronounced blood–brain barrier disruption and prominent glial response when compared to ATCC cell line.These findings indicate that immortalised cancer cell lines obtained from different cell banks may have diverse characteristics and behaviour in vivo.Cancer research has received much attention and funding over the past decades, reflecting its increased incidence and significance as a public health problem. Carcinogenesis is a multifaceted and complex disease process, making malignancies inherently difficult to treat, while at the same time presenting multiple pathways for investigation as management options. Novel treatments targeting these different pathways can then be assessed, although tumours in the brain have been excluded from many clinical trials due to the restrictive nature of the blood–brain barrier (BBB), often making brain metastases not accessible to novel treatments [1,2]. Metastatic brain tumours are present in 22-30% of patients diagnosed with breast cancer [3-5], therefore making animal models of brain metastases important tools to explore adequate treatment options for this aspect of the disease.The process of brain metastases involves cells from a primary tumour entering blood vessels, avoiding death signals in the circulation, then undergoing extravasation through the BBB [6]. The BBB is a dynamic interface between the cerebral circulation and brain tissue, and acts to pro