Dr. David Sirbasku's research at The University of Texas Medical School at Houston addressed the fundamental 100-year old problem of "how steroid hormones cause the growth of the early forms of such cancers as those of breast, uterus, prostate, kidney and pituitary". Many competing hypotheses were under evaluation by the scientific community. Using new serum-containing and serum-free defined cell culture technology, Dr. Sirbasku demonstrated that the immunoglobulins of the Secretory Immune System acted as negative regulators (i.e. the brakes) to prevent growth of early cancers of these tissues, and that steroid hormones such as estrogens and androgens acted as positive regulators (i.e. the accelerators) to stimulate the growth of the early tumors. This discovery had many new medically and commercially important applications that are now the intellectual property base of Signe BioPharma Inc.