Table 1.

Main and secondary keywords used for literary search

Main key words	Secondary key words
ALDH1A1 Cancer Tumor Neoplasia Tumor microenvironment	Preclinical study     Clinical study     Stemness     Drug resistance     Proliferation     Migration     Invasion     Vitality     Survival     Apoptosis     Angiogenesis     Metastases     Immuno evasion

Secondary key words were utilized in combination (by using “AND”) with the main key words. The main keywords were combined by using “OR” and are reported in left column. ALDH1A1: Aldehyde dehydrogenase 1A1