• Many substances in our environment exert estrogenic activity; many have been around for long and have been happily ignored – or at least benevolently neglected. Their chemical structure may or may not resemble that of steroids; hence, their estrogenic effects are sometimes totally unexpected. These effects may be weak, cumulative or sufficient to block "true" estrogen binding to appropriate receptors; some are able to mimic estrogens, both in vitro and in vivo. More and more, they are being considered undesirable or even deleterious to health, as suspected contributors to abnormalities in estrogen-target tissues of both sexes.

• The temperature of cancerous breast tumor is higher than that of benign tumor or normal breast tissue, probably because of the heat generated by the increased blood flow to supply the growing tumor. This temperature differential can be detected by sensors placed in the bra. Here is an idea for a radiation free novel method to screen young women for breast cancer.

• Human papillomavirus infection has been implicated as a cause for cervical cancer. Now it is indicated that this virus may also be involved in the development of non-cervical genital tract cancers. Vaccine against this virus will be of benefit to prevent these cancers.

• Dendritic cells, a heterogeneous group of nonphagocytic cells of the immune system, when fused with tumor cells and injected into animal, induce tumor-specific cytotoxic T cells which recognize tumor cells and destroy them. Immunization with this fusion cells, not only protects against primary tumors, but also rejects established metastasis. Dendritic cells can be easily obtained from blood or bone marrow.

• In a study conducted in Taiwan, vaccination against hepatitis B virus among children reduced the infection rate significantly and this reduction in virus infection was accompanied by a drop in liver cancer among the children.

• Increased risk of several cancers, especially that of liver, is observed among diabetics. Diagnosis of diabetes has been found to precede the diagnosis of liver cancer by many years.

• New experimental strategies enable to determine quantitatively the efficiency of the repair of pathogenic messenger RNAs by ribozymes. This makes possible rational ribozyme engineering to augment its effectiveness in a therapeutic setting.

• The type of DNA alterations present in invasive lung cancer is found in the chromosome from lung tissue of current and former smokers, indicating that molecular changes caused by smoking persist after cessation of smoking. These molecular markers may be employed to identify high-risk subjects among smokers and for monitoring their response to preventive intervention.

• After successful surgery and/or radiotherapy, success of chemotherapy depends ultimately on the rate and extent of drug resistant cancer cell populations which either develop with time or form part of the original, heterologous tumor. Preven-tion, circumvention or reversal of the multidrug resistance (MDR) phenomenon remains an elusive goal; the identification of MDR cells with a rapid, reliable method is of great interest – to guide future therapy and to identify novel sensitising agents.

• The plant kingdom is a rich source of compounds, the phytochemicals, which possess a myriad of beneficial biological effects; some of them may act in preventing cancer. Flavonoids, a group of aromatic compounds that are present in fruits, vegetables, nuts, seeds, tea, coffee, and wine as well as in the stems, leaves, flowers, bark, and roots of most plants have inhibitory effect on cell growth and angiogenesis.

• The results of a family study show that on chromosome 1, in a small region of the long arm, is a gene which, when excessively expressed, might act as a cancer-promotor. The gene has been called HPC1 (for hereditary prostate cancer 1) and is considered by some researchers as a "major contributer to the risk of prostate cancer."

• Small proteins or polypeptides that are specifically overexpressed in certain cancer cells can be used as "tumor markers" for obtaining information about the disease. In breast cancer cells one such tissue, polypeptide antigen Cytokeratin 8, is frequently overexpressed and its measurement provides information about recurrence or metastasis in patients with breast cancer. It therefore can serve as a monitoring tool.

• Nitric oxide produced biologically may promote tumor growth. Inhibition of an enzyme that synthesizes this small molecule is found to reduce growth of tumors expressing this enzyme. Use of such specific inhibitors could be a novel strategy in cancer treatment.

• Apoptosis or programmed cell death is a natural phenomenon and is very complex. Research is slowly unraveling mechanisms underlying this process. Endogenous cellular enzymes play a crucial role for the organized disassembling of the cell. A group of proteolytic enzymes known as caspases (cysteine aspartases) that participate in the induction of apoptosis are under intensive study. These enzymes can be targeted for modulation by drugs for the benefit of cancer patients.

Glossary

• A glossary of unfamiliar words and jargons in Cancer Watch, October 1997.