NT5E and breast carcinoma: 101), which have tumour-initiating ability and play a critical role in tumour metastasis, relapse and chemoresistance (Ref. 102). Our results evidenced a reduction in CD73 expression and enzymatic activity in cervical spheres when compared to monolayers (Ref. 99). Interestingly, our in silico analyses have supported our in vitro results, showing that three-dimensional spheres derived from cervical, thyroid and breast cancer presented decreased expression of CD73, when compared to their adherent counterparts (Ref. 99).