Fig. 2

Evolution of cancer therapies over the years. The initial approach represents conventional therapy, which is based on the employment of unspecific chemical and physical agents (chemo and radiotherapy) that target general cellular processes occurring in both healthy and cancer cells and that do not take into account molecular alterations exhibited by the tumors. In the second approach , the molecular screening of cancer cells led to the development of selective drugs based on altered molecular features of malignant cells. This approach is particularly represented by tyrosine kinase inhibitors and monoclonal antibodies, which specifically target tumor cells. It is based on single-biopsy studies and does not take into account molecular alterations exhibited by microenvironment (ME) cells or tumor heterogeneity. The current approach shows that, lately, not only the tumor, but also its ME, have been mapped, which contributed to the development of selective drugs designed for both malignant and ME cells. The ME alterations more frequently targeted by molecular drugs are the ones observed in several types of cancers, such as angiogenesis, inflammatory processes and MMP overexpression. Again, this approach is based on single-biopsy studies and does not account for tumor heterogeneity. The future approach for cancer treatment shall account for the whole molecular heterogeneity, which is differentially exhibited by malignant and ME cells and unveiled by multiple biopsies