NOTCH1 and acute lymphoblastic leukemia: Multiple signaling pathways and molecular regulators collaborate with NOTCH1 signaling, contributing to T-ALL pathogenesis through several mechanisms, such as favoring cell proliferation and survival through specific surface receptors or by impaired cell cycle control, increasing the fitness of leukemic cells by the modulation of their metabolic demands, or guiding T-ALL cells to specialized niches where they can expand uncontrollably.