CA9 and neuroblastoma: This concept was supported by: (i) our data showing that treatment with JQ1 decreased the mRNA and protein levels of CA9 in several NB cell lines, including those derived from TH-MYCN tumors; and (ii) previous studies showing that JQ1 impairs hypoxia in triple-negative breast cancer through its ability to interact with HIF-1α and inhibit its transcription activity [24,36].