Oxidative stress has been found to modulate tumour cell dormancy through the inactivation of Kelch-like ECH-associated protein 1 (Keap1) and translocation of Nrf-2 into the nucleus, leading to the promotion of neurogenic locus notch homolog protein 1 (Notch1) and sonic hedgehog protein (SHH) transcription and subsequently activating downstream signalling [160, 161]. Here, SHH is linked to neoplasm.