The Role of Stroma in Tumour-Host Co-Existence: Some Perspectives in Stroma-Targeted Therapy of Cancer

Cancer grows at the expense of the host as a parasite or superparasite following the second law of thermodynamics (conservation of energy).When the cancer cell progresses via replication to the special state called "spheroid", a new phase begins with its intimiate interaction and development of responses from the stroma which together assist in the formation of a full blown cancer.Among the processes involved are the development of blood vessels and lymphatic channels which are essential for maintenance and further growth of the cancer mass.In this way the condition of "parasitism" is completed with simultaneous suppression of the immune response of the host to the histoincompatability of the tumor mass.Stroma/parenchyma promotes cancer invasion by feeding cancer cells and inducing immune tolerance.The dynamic changes in composition of stroma and biological consequences as feeder of cancer cells and immune tolerance can give a perspective for rational drug design in anti-stromal therapy.There are differences between normal and cancer cells at subcellular level such as compartmentalzation and structure of cytoskeleton and energy distribution (that is low generally, but locally high in normal cells).In cancer cannibalism of normal cells, the growing cancer mass is a factor for progression and invasion.