Hormones, vitamins, and growth factors in cancer treatment and prevention. A critical appraisal.

BACKGROUND

Hormones, hormone agonists, hormone antagonists, vitamins and their synthetic analogues, and growth factors are currently the most widely used anticancer drugs. Although in many cases they provide dramatic results, in other cases their effects are conflicting. A critical appraisal of the effects of these drugs is needed.

METHODS

To evaluate the potential therapeutic and preventive roles of these drugs as well as their areas of controversy, data published in the literature in the last two decades are reviewed in this article, and the author's personal findings are also reviewed.

RESULTS

Hormones, hormone agonists, hormone antagonists, vitamins and their synthetic analogues, growth factors, and cytokines are replacing conventional cancer therapies (chemotherapy, surgical therapy, and radiation therapy) for many purposes, and recently became the "fourth arm" of cancer treatment. However, their mechanisms of action have not yet been elucidated. This article critically reviews the mechanisms of their action on cancer cells (specifically, DNA, RNA, oncogenes, and antioncogenes); their role in cancer cell division, cell cycle, apoptosis, and angiogenesis; and their relation to human cancers. Since hormones, vitamins, growth factors (GFs), and GF receptors play a cardinal role in multistage carcinogenesis, using monoclonal antibodies to develop novel hormone antagonists, vitamin synthetic analogues, and GF inhibitors will be of paramount significance for neoadjuvant systemic therapy and cancer prevention.

CONCLUSIONS

It is hoped that the data presented in this review regarding the role of hormones, hormone agonists, hormone antagonists, vitamins, growth factors, and growth factor inhibitors will provide a rationale for designing effective new cancer chemoprevention strategies and clinical trials.