Among the highlights in the January 1999 Cancer Watch issue are: Fatty Acids, Insulin Resistance and Breast Cancer Risk, Dietary Prevention in Breast Cancer, The Interpretation of Breast Magnetic Resonance Imaging (MRI), How Do Adolescents Get Their Cigarettes?, Mutant Salmonella to Treat Cancer, Differentiation of Metastatic and Non-Metastatic Tumor Cells, Boron Neutron Capture Therapy for Cancer, A New Tumor Marker for Renal Cell Carcinoma, Decoy Receptors Deceive Cell Death, Chromosome Used to Arrest the Growth of Breast Cancer Cells, Campaign Targets Oral Complications of Cancer Treatment, Technology Update: Nucleic Acid Microarrays, Meeting Report: American Society of Hematology and Miami Beach, FL, December 4- 8, 1998.

• Fatty Acids, Insulin Resistance and Breast Cancer Risk
• Dietary Prevention in Breast Cancer
• The Interpretation of Breast Magnetic Resonance Imaging (MRI)
• How Do Adolescents Get Their Cigarettes?

• A genetically modified strain of Salmonella is found to reduce tumor growth without producing lethal septic shock. This strain specifically targets tumor cells and grows in them.

• Malignancy is thought to be the consequence of uncontrolled cell growth; however, the clinical outcome is more often than not the result of the ability of some tumor cells to spread and give rise to metastatic foci. Tumors are notoriously heterogeneous at any time; diagnostic methods which would allow for a precise evaluation of post-surgical specimens for metastatic risk (substituting highly subjective judgements such as "poorly differentiated") are obviously very important.

• A new radiation therapy, the boron neutron capture therapy (BNCT) that requires synthesis of tumor-targeting agents containing a large number of boron atoms is being developed to treat cancer. DNA-like oligomers that are small enough to enter cell nucleus and subsequently bind to it are being developed by a team of scientists. These boron-tagged oligomers can be irradiated with neutron to produce high-energy particles which in turn will destroy the cells.

• According to a general statement of the WHO, early detection of cancer could improve the rate of cure by one third; compared to these expectations, the reality is disenchanting. The mushrooming of commercially offered "cancer" tests has not improved cure rates, survival or quality of life by much; this does not mean that the search and cautious evaluation of new markers should be abandoned. The increasing insight into the molecular biology of malignant growth is reason for optimism. Although there are several tests with diagnostic relevance for prostate cancer, gastrointestinal tumors etc. available, a satisfactory marker for renal cell carcinoma has been missing, so far. There is hope that the recently developed Tu M2-PK may fill this gap.

• The immune system keeps an eye on all cells of the body and if they become infected by virus or become abnormal due to mutation like cancer, a protective immune reaction takes place and the harmful cells are eliminated in various ways. One of the methods is induction of apoptosis of the marked cells by substances produced by the immune system cells. These substances interact with specific receptors on the cell surface and trigger apoptosis. Fas/FasL is one such receptor/ligand system in eliminating abnormal cells. Some cancer cells are found to evade immune surveillance and one of the mechanisms is found to be production of large quantities of decoy receptors that compete with FasL in preventing apoptosis, thus giving these cancer cells growth advantage.

• When normal human chromosome 3 was introduced into human breast cancer cells growing in a laboratory, most of the cells reached a state of permanent growth arrest. This growth arrest was found to be associated with inhibition of telomerase activity in these cancer cells.

• One of the side effects of some cancer therapies are oral complications. Among the most common complications are painful inflamed gums, mouth ulcers, bleeding, infection and salivary gland dysfunction leading to dry mouth and rampant tooth decay. Most cancer patients, however, do not know that proper oral care can prevent or minimize these adverse effects. The National Institute of Dental and Craniofacial Research (NIDCR) is launching an awareness campaign in partnership with the National Cancer Institute and other related establishments to encourage communication between oncology and oral health care providers and to give patients the tools they need to be active participants in their cancer care.

• Nucleic acid microarray technique is based on a critical feature of DNA double helix – the complementarity of the two strands. A known sequence of nucleic acid is immobilized on a matrix and labeled nucleic acids, when allowed to interact with it, will hybridize and can then be identified. Advantage of microarray technique is that a large number of different nucleic acid molecules could be attached to a matrix that allows identification of a large number of molecules in a short period of time.

• In this meeting several reports were presented that included safety and effectiveness of combination chemotherapy against hematologic cancers. Reports show that combination of cyclophosphamide, Ara-C and topotecan (CAT) is safe and effective in newly diagnosed acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) and chronic myelogenic leukemia (CML). Treatment with topotecan is an active combination for MDS as well as for chronic myelomonocytic leukemia (CMML), particularly for patients with poor prognosis. Another group of compounds, bisphosphonates, not only prevents bone resorption but appears to inhibit the growth of tumors as well in multiple myeloma patiemts.

• Light-skinned individuals, who do not tan well and expose themselves to ultraviolet light (UV), show an increased tendency to develop skin cancer. UV radiation damages the DNA of their keratinocytes; normal repair mechanisms usually suffice to control this damage, but can eventually be overwhelmed. The skin lesions are gradual and start with solar (actinic) keratoses, considered as pre-malignant; since they are on the skin, visible, well circumscribed and characteristic, they can be readily recognized and treated. Left on their own (and stimulated by further, repeated and prolonged UV exposure) they tend to proceed towards malignancy: squamous or basal cell carcinomas. In Western society, non-melanoma skin cancers are among the most common; they are easy to observe, grow slowly and are relatively indolent in early stages. Their prevention is a worthwhile and achievable goal. Data presented here do not include the melanomas, since the role of photocarcinogenesis in their development is different and much more controversial.

Glossary

• A glossary of unfamiliar words and jargons in Cancer Watch, January 1999.