Transparent reporting of experimental parameters in assays measuring phenotypic steps in metastasis.

Metastasis is key to cancer mortality. Understanding its biology is vital for developing strategies to prevent and treat metastasis. Phenotypic assays to either study metastasis or evaluate anti-metastatic drugs are widely used in preclinical research. This technical note discusses the adherence of reporting essential experimental and methodological parameters in chemotactic invasion assays in vitro and spontaneous metastasis assays in vivo. Following the analysis of 130 recent (< 5 years) research papers, several shortcomings in reporting were identified. Therefore, we strongly argue to increase experimental rigor which should result in a significant improvement with respect to reproducibility of preclinical metastasis research.