Among the highlights in the May 1998 Cancer Watch issue are: Promising Drug to Starve Growing Tumors, Screening of Lung Cancer by Spiral CT Scanner, UV Radiation-Induced p53 Mutation and Skin Cancer, Virtual Reality Technology to Plan Surgery, Breast Cancer Diagnosis by Computers, NCI Needs More Participants for Cancer Treatment Trial, Stromelysin, an Enzyme Involved in Tissue Remodeling, Cancer Vaccines: Emerging Initiatives, DNA, The Master Molecule: Gene Repair vs Gene Replacement, Oxford Analysis Extends Recommendations for Tamoxifen in Early Breast Cancer, Association of Chemical Detoxification Gene and Breast Cancer, Mechanisms of E-Cadherin Inactivation in Breast Cancer Cell Lines, Germline Mutation in Familial Gastric Cancer, Deep Venous Thrombosis and Cancer, Clinical Debate Over Occult-Blood Test for Colorectal Cancer and MRI Helps to Elucidate Natural History of Breast Cancer.

• Promising Drug to Starve Growing Tumors
• Screening of Lung Cancer by Spiral CT Scanner
• UV Radiation-Induced p53 Mutation and Skin Cancer
• Virtual Reality Technology to Plan Surgery
• Breast Cancer Diagnosis by Computers
• NCI Needs More Participants for Cancer Treatment Trial
• Stromelysin, an Enzyme Involved in Tissue Remodeling

• Conceptually, the immune response is expected to distinguish between self and non-self, good or bad. Malignant growth is "bad" and sufficiently "different"; why then is the host, most of the time, totally inept to mount an effective response and deal with the challenge? To this and many ensuing questions, a great many explanations have been put forward. As yet, none is satisfactory. Based on the historic success of vaccination, both preventative and therapeutic, cancer vaccines would appear to be the most natural and simplest solution for the treatment, cure and even prevention of cancer. However, the straightforward extrapolation from infectious agents to malignant cells is still, with very few and often anecdotal exceptions, successfully evading practical, large-scale application. Clinicians and their patients continue being torn between unrealistic expectations and the hope of a miracle innovation, born through tenacity and serendipity.

• Primary defects of genetic disease can in principle be treated with compounds that bind to and repair mutated nucleic acid sequences. The rudimentary principles of gene repair are presented.

• A meta-analysis of 55 randomized trials among 37,000 women with early breast cancer suggests that five years treatment with tamoxifen can offer protection against cancer recurrence and death to a larger group of women than has been supposed.

• Alteration of genes that code enzymes responsible for metabolizing a variety of agents may influence breast cancer risk. Loss of the detoxifying enzyme glutathione S-transferase gene or the presence of a mutated form that lowers the activity of this enzyme is found to be associated with increased risk of breast cancer.

• Reduced expression of cell adhesion protein E-cadherin is found to be associated with increasing cell proliferation, invasion, and metastasis of certain solid tumors. Significant deletion of both alleles of the gene is found to be responsible for this inactivation. Hypermethylation of the promoter site that is known to inactivate the gene is also observed in some cases. Restoration of this gene function is observed by various agents such as tamoxifen and retinoic acid. Those cell lines which show significant loss in both alleles will not response to these agents. Methylation-inhibiting agents may reverse the effect to some extent in cell lines displaying methylation in promoter site.

• Inherited mutation in the gene that produces cell adhesion, protein E-cadherin, may predispose individuals to gastric cancer. Such mutations produce inactive protein that disrupts normal cell-cell adhesion initiating uncontrolled cell proliferation.

• There is an association between cancer and primary venous thrombosis. However, all patients presenting venous thrombosis need not be screened aggressively for hidden cancer. Simple methods of screening to look for cancer in those who show signs and symptoms are recommended.

• Various expert panels and professional organizations have recommended fecal occult-blood tests for all patients. Some question this decision. They believe that these tests are not specific or sensitive enough for mass screening. Views of opponents and proponents are presented.

• Though not very specific in breast cancer detection, magnetic resonance imaging detects tumor vascularity and is highly sensitive. High resolution images obtained by sophisticated computer programming can significantly increase the specificity of this noninvasive cancer detection method.

Glossary

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