Croci GA, et al. - Researcher conducted a round-robin test on a tissue microarray to assess the reproducibility in evaluating the biomarkers of outcome in mantle cell lymphoma. They evaluated cytological subtype, Ki67-index and expression of p53 and SOX11 on 20 diagnostic tumour samples by eight participating labs independently. They illustrate that the evaluation of the proliferation index by counting the Ki67 positive cells as well as the assessment of SOX11 and p53 expression status is reproducible between labs. They further assessed all cases in this cohort for gene expression signatures and of TP53 gene alterations. Given the good reproducibility when guidelines of assessment are used, the biomarker studied in this inter-laboratory test displays potential candidates to be enhanced for risk-stratification in the forthcoming clinical trials.