TOP1 and neoplasm: Using SW620 tumor spheroids grown on microfluidic tumor-on-chip platform, the combination of 7-ethyl-10-hydroxycamptothecin [SN38; the active metabolite of the Topoisomerase I (TOP1) inhibitor-irinotecan] and AZD0156 potentiate DNA double strand breaks and induced cell death and reduced proliferation of the cells [124].