This chapter is a monography concerning the possible role of tissue stiffness in the human carcinogenesis as well as its possible impact in the diagnosis, prognosis, and treatment of the malignancies. Cancer is a very serious health problem in mankind, with an increasing prevalence and incidence worldwide. Although in the last years, several diagnostic and therapeutic approaches were suggested and made available for managing human malignancies, the outcome of patients and their quality of life are still poor for most of these different forms of neoplasms (Torre LA, Siegel RL, Ward EM, Jemal...