The rapid progression from aggressive primary
cancers into locally advanced and invasive and/or metastatic diseases remains a big obstacle for an early diagnosis and curative therapeutic intervention for
cancer patients. The late-stage
leukemias and disseminated and metastatic
sarcomas,
melanomas,
brain tumors and epithelial
cancers are the devastating diseases associated with a high rate of recurrence
after treatment with the conventional clinical
therapies including surgery, ionizing radiation, hormonal
therapy and systemic
chemotherapy, which generally lead to the death of patients. Therefore, the establishment of the molecular events underlying
cancer initiation and progression into locally invasive and metastatic diseases is of major interest in basic
cancer research as well as for the development of new effective clinical therapeutic options against the recurrent and lethal
cancers. Recent advances have led to the identification of specific oncogenic products that are implicated in the malignant transformation of adult stem/progenitor cells into leukemic or tumorigenic and migrating
cancer stem/progenitor cells during
cancer progression. Of therapeutic interest, the molecular targeting of deregulated signaling elements in
cancer stem/progenitor cells and their local microenvironment represents a new potential strategy for the development of more effective clinical treatments against aggressive
cancers. Particularly, the combined use of chemotherapeutic drugs to eradicate
cancer-initiating cells with hematopoietic stem cell or genetically-modified stem cell transplant is emerging as potential
cancer treatments that hold great promise in the area of clinical
cancer research. These targeting and stem cell-based
therapies may offer the ultimate hope for treating and even curing the patients diagnosed with locally advanced
cancers at high risk of recurrence, metastatic and/or relapsed
cancers in the clinics.