CD44 and breast cancer: The HH signaling pathway activation contributes to enrichment of the CD44+/CD24− population [192] and chemoresistance associated with BCSC [144], while its dysregulation, observed as the overexpression of Sonic hedgehog (SHH), Desert hedgehog (DHH), and GLI1, is correlated with a worse prognosis and more advanced stages of BC [192,193].