Tumor-initiating cells (TICs)

Tumor-initiating cells (TICs), often referred to as cancer stem cells (CSCs), are a distinct subpopulation of cells within a tumor that possess the capacity for self-renewal and the ability to generate the heterogeneous lineages of cancer cells that comprise the bulk of the tumor. These cells are characterized by their high tumorigenic potential and are frequently resistant to conventional chemotherapy and radiotherapy, which often target rapidly dividing cells while TICs may remain quiescent. TICs play a critical role in cancer recurrence and metastasis, as even a small number of surviving TICs can regenerate an entire tumor after treatment. Therapeutic strategies aiming to eradicate TICs focus on inhibiting specific signaling pathways like Notch, Hedgehog, and Wnt, or targeting surface markers such as CD133 and CD44. However, the plasticity of cancer cells—where non-stem cancer cells can revert to a TIC state—remains a significant challenge for clinical efficacy.

Other names

Cancer stem cellsCSCsTumor-propagating cellsCancer-initiating cellsTumorigenic cells

Drugs targeting tumor-initiating cells typically act by inhibiting highly conserved developmental signaling pathways such as Wnt/beta-catenin, Hedgehog, and Notch, or by targeting specific surface markers like CD44 and CD133 to induce apoptosis or differentiation in the stem-like population.