Stem cell biology in thyroid cancer: Insights for novel therapies

Figure 1 Histological images showing subcutaneous thyroid cancer mouse model. A: Hematoxylin and eosin stained microphotograph of tumor xenografts engrafted human thyroid cancer cell line (K1) with adipose-derived stem cells (ASCs) (× 100); B: HE microphotograph of lung metastasis (red arrows) in the group transplanted with K1 cells and ASCs (× 200). Methods of image acquisition: Tumor and organs removed from mouse, photographed, and stored in 10% neutral buffered formalin for paraffin sectioning and HE staining. Tumor tissue were sectioned and stained with HE[28].

Figure 2 Representative tumor from severe combined immunodeficiency mice injected with: (A) K1 + ASCs and (B) K1 alone. ASCs: Adipose-derived stem cells.

Figure 3 Adipose-derived stem cells promote tumor growth of papillary thyroid cancer cells. K1 cells alone and K1 cells with ASCs (5 x 10⁵ cells each) were injected subcutaneously into nude mice (n = 5, each group)[28]. ASC: Adipose-derived stem cell.

Figure 4 A schematic representation showing cancer stem cells resistance to chemo-and radio-therapy causing tumor to relapse. Cancer stem cells (CSCs) (yellow) with differentiated cells committed to a particular lineage (red). Ability of CSCs to resist anti-cancer therapy due to various mechanisms and ability to proliferate into heterogeneous group of cells cause tumor to relapse. HMGA2: High mobility group A2; ABCG2: ATP-binding cassette sub-family G member 2; MDR1: Multi-drug resistance protein-1; IGF: Insulin-derived growth factor; EGF: Epidermal growth factor; bFGF: Basic fibroblast growth factor.