Among the highlights in the March 1998 Cancer Watch issue are: Cancer Risk and Cosmetic Breast Implant, Alcohol and Breast Cancer in Women, Cancer Screening by Whole-Body Positron-Emission Tomography, A New Program by NIH to Study Genes for Environmental Risk, Good News on the Cancer Front, Dietary Fat and Breast Cancer, The Urokinase Plasminogen Activator System in Cancer, New Strategies Against Cancer: Gene Therapy for Tumor Antiangiogenesis, Galectin-4: Another Tumor Marker?, DNA, The Master Molecule: New Roles for Double Stranded DNA, Novel Mechanism for Estrogen Action, American Society of Hematology Meeting Report, Radiation Therapy-Induced Atypical PAP Smears, FHIT, a Multiple Tumor Suppressor Gene and News Media Influencing Public Health Perception.

• Cancer Risk and Cosmetic Breast Implant
• Alcohol and Breast Cancer in Women
• Cancer Screening by Whole-Body Positron-Emission Tomography
• A New Program by NIH to Study Genes for Environmental Risk
• Good News on the Cancer Front
• Dietary Fat and Breast Cancer

• The serine proteinases: urokinase-type plasminogen activator (u-PA) and plasmin are part of a system which also consists of the serpins antiplasmin PA-1 and PA-2 and the u-PA receptor(s). There is now quite an accumulation of evidence that this system is actively involved in the selective degradation of extracellular matrix, which in turn allows increased cell migration. Cancer cell proliferation by itself is not the direct cause of metastasis; the tendency of at least some malignant cells to cross otherwise restricted boundaries is far from being clarified – but a complex interplay between serine proteinases and its inhibitors, integrins, endocytosis receptors and growth factors is known to facilitate cell mobility, invasion and finally colonization. The u-PA system is one of the important components of this cascade and lends itself to well-established and not excessively elaborate determination methods; this has contributed to a vastly improved understanding of the malignant process with the perspective of new targets for antiinvasive and antimetastatic therapy.

• Solid tumors needs blood vessels to sustain their growth and are equipped with genes that can produce factors to stimulate new blood vessel formation. A novel strategy to inhibit this process will be to introduce gene to counteract this process. Though animal studies show that this type of gene therapy targeted to a particular organ is feasible, there are still many challenges that have to be overcome before this technique can be successfully applied to humans.

• Tumor markers, that is, proteins that are specific for certain types of cancer are very important in diagnosis and sometimes in determining treatment effect. Galectin-4 belongs to a class of proteins called lectin which bind to the sugar molecule galactose. This protein essentially is present inside the cell but can be externalized in response to various stimuli and can be determined on the cell surface. Galectin-4 has been found in all in situ and invasive breast cancers while absent in normal epithelium. It is present in both normal and malignant cells of the colon and ovary. These observations are still at an early stage but indicate that in some tumors Galactin-4 can be used as a tumor marker.

• Double stranded RNA complementary to a coding region of a gene in the nematode C. elegans is very effective in interfering with gene expression at the level of phenotype, RNA and protein with specificity and reproducibility. A possible mechanism and biochemical pathway of this mystifying and astounding observation is presented.

• Estrogen may damage DNA when one of its metabolites, equilenin, forms a novel adduct with it. Equilenin is not naturally found in humans, but is a minor component of the very popular drug Premarin used by approximately 10 million women in the US.

• New lab technique to detect residual leukemic cells was discussed in the meeting. This highly sensitive technique, known as real-time polymerase chain reactin (RT-PCR), can detect the cells that persist in the majority of patients. The latest innovation in continuous detectin of disease, RT-PCR acts as a PCR and a flow cytometer at the same time. No PCR processing is required thus reducing contamination. Another report describes the role of retinoic acid in the treatment of acute promyelocytic leukemia (APL). Addition of this agent to chemotherapy regimen can significantly improve survival of such leukemia patients by as much as 30%.

• Radiotherapy, after surgery of cervical cancer, may produce changes in the cells that could lead to misinterpretation of follow-up PAP smear.

• The FHIT gene, at chromosome region 3p14.2, encodes a mRNA of 1.1 kb and a 16.8 kDa protein, with diadenosine triphosphate hydrolase activity. It includes one of the most active of the common human chromosome fragile regions and sites of homozygous deletions in tumor DNAs in a variety of human cancers (comprising a familial kidney-tumor associated translocation break). Recent evidence suggests that FHIT is a tumor suppressor gene, which can be inactivated by carcinogens; deletions are common because it straddles the FRA3B fragile site. Absence of its product FHIT protein is advantageous to expansion of tumor cell clones and other biological processes contributing to tumorigenesis.

• Purpose of scientific research is to look for the truth, that is, the true mechanism underlying a phenomenon. Achieving this is not only intellectually challenging, but the path is woven with social, economic, and political dynamics hard to traverse. Research needs financial support. Pressure from various interest groups tries to dictate the direction of research. In the beginning of this century research in physics was heavily favored and we have seen the result. Now is the era of biology and biochemistry and it will extend far beyond the next century. With the advances in electronic news dissemination and the complexities in health research, comes the added responsibilities on the part of the reporters, not only to report it first, but correctly. How the information is disseminated has a great impact on public perception of science.

Glossary

• A glossary of unfamiliar words and jargons in Cancer Watch, March 1998.