SLC29A1 and cancer: Furthermore, screens to assess off-target effects of tyrosine kinase inhibitors revealed the potential of several tyrosine kinase inhibitors such as lorlatinib, gefitinib, vandetanib, and erlotinib to not just inhibit their designated target but also hENT1 causing nucleotide transport inhibition in non-cancer and cancer cells (Figure 2A,D) [67,68,69].