The constitutive expression of CD70 has been described in various haematological and solid tumour types. In addition, the co-expression of its receptor in tumours has been demonstrated, mediating tumour cell proliferation. Although CD70 expression is a prerequisite to enrol patients in solid tumour clinical trials using anti-CD70 immunotherapy, there is currently no standardised test to evaluate CD70 expression. These differences in immunohistochemistry (IHC) protocols make it challenging to compare the expression levels that were obtained in different studies, pointing out the need for one uniform methodology. In this retrospective study, over 600 tumour samples from different solid and haematological malignancies were analysed while using one validated IHC method. CD70 and CD27 expression was demonstrated in a broad range of tumour types. In solid tumours, 43% demonstrated CD70 positivity with the highest degree in renal cell carcinoma (79.5%). Kaposi sarcoma showed no CD70 expression on the tumour cells. In lymphoma samples, 58% demonstrated CD70 positivity. Moreover, the co-expression of CD70 and CD27 was observed in 39% of lymphoma samples. These findings highlight the need to further explore anti-CD70 therapies in a broad range of CD70 expressing tumour types and in doing so, implementing one standardised protocol to define CD70 overexpression to use it as a diagnostic tool.

Recurrent chromosomal translocations are found in many blood and solid cancers. Balanced translocations, frequent in lymphoid malignancies, lead to the formation of two aberrant derivative (der) chromosomes. This event often leads to overexpression of an oncogene. In many cases, the expression of an oncogene is not enough to produce a malignant phenotype; however, most part of the studies focus on the events involving the chromosome where the oncogene is located, but rarely the other der chromosome where other oncogenic alterations may potentially arise. Mantle cell lymphoma (MCL), an aggressive B-cell non-Hodgkin lymphoma, is a perfect example of this. In 85% of the cases, it is characterized by the translocation t(11;14), which leads to the overexpression of cyclin D1 (CCND1) gene which results juxtaposed to the immunoglobulin heavy chain (IGH) gene on the der14 chromosome. This feature alone is not sufficient to induce oncogenesis. Here we focused on the der11 chromosome. We demonstrated that expression of 88 genes located in a 15mb region close to the translocation breakpoint on the der11 was deregulated both in the GRANTA-519 MCL cell line and in B-cells from MCL patients. We found that a large segment of der11containing deregulated genes was relocated from its normal position in the nuclear periphery towards the center of the nucleus in close proximity to the nucleolus where the abundant nucleolar protein nucleolin binds a subset of genes located close to the breakpoint and activates their expression. This finding allowed to identify new potential oncogenes involved in MCL and the mechanisms of their upregulation.