Among the highlights in the October 1998 Cancer Watch issue are: High-Dose Chemotherapy in Breast Cancer, Psychosocial Care for Cancer Patients, External Beam Radiotherapy vs. Implant for Localized Prostate Cancer, Breast Electropotentials: A New Test for Cancer, Centrosome Function and Malignant Transformation, Cyclooxygenase and Colon Cancer, A Protein that Induces Hormone Insensitivity to Prostate Cancer Cells, Is the BRCA1 Gene also a Potential Human Prostate Cancer Suppressor?, A New Drug Approved for Bladder Cancer, Plasma Estrogen Levels and Breast Cancer Risk, Can Jet Lag Cause Cancer?, Autopsy Reveals More Cancer Cases, The NCI Awards Grants to Study Cancer Survivors, Sentinel Lymph Node Biopsy in Breast Cancer and The Tamoxifen Trials: A Cautious Critique.

News in Brief

• High-Dose Chemotherapy in Breast Cancer
• Psychosocial Care for Cancer Patients
• External Beam Radiotherapy vs. Implant for Localized Prostate Cancer
• Breast Electropotentials: A New Test for Cancer

• Centrosome, the tiny organelle, associated with microtubule formation and participates in chromosome segregation during cell division may play an important role in the progression of cancer. Duplication of centrosome is essential for cell division and it is found to be influenced by protein phosphorylating enzymes. One of these enzymes, STK15, is found to be overexpressed in many human cancer cells. Normal cells engineered to overexpress this enzyme show abnormality in centrosome numbers and chromosome segregation. These altered cells also grow in culture medium and form colonies typical of cancer cells.

• A microsomal enzyme system known as cyclooxygenase that participates in prostaglandin synthesis may be associated with increased risk of colon cancer. Nonsteroidal antiinflammatory drugs such as aspirin may prevent colon cancer by inhibiting this enzyme.
  

• It is well known that most prostate cancer cells are initially sensitive to androgen withdrawal; but eventually they lose this property and grow in the absence of hormone and spread to other organs. One of the mechanisms underlying this phenomenon may be overexpression of a cell membrane protein called caveolin that is involved in signal transduction activities. Inhibition of this protein expression is found to restore hormone sensitivity.

• Germline mutations of BRCA genes are firmly associated with 80% of families with high incidence of breast or ovarian cancers. There is good evidence that intact BRCA1 and BRCA2 genes are tumor suppressors and that their mutations increase cancer susceptibility, possibly in conjuction with other suppressor mutations, such as p53. Although the majority of prostate cancers are thought to be sporadic, a linkage between breast, ovarian and prostate cancer has been recently found in certain families.

• A new anthracycline analog is approved by the US Food and Drug Administration to treat patients with carcinoma in situ of the urinary bladder. This drug is recommended to be administered intravesically. Clinical trial shows 20% complete response rate.

• High circulating levels of estrogens in postmenopausal women may increase the risk of breast cancer, especially for those who have not used hormone replacement therapy. Higher estrogen levels may have both beneficial and adverse effects. However, reducing the levels or activity of endogenous estrogen can be a promising way to prevent breast cancers in postmenopausal women.

• The hormone melatonin is secreted by the pineal gland in response to darkness and has many physiological functions. Jet lag disrupts the function of pineal gland. The epidemiologic observation that a group of Finnish flight attendants had high rate of breast cancer may be related to disruption of melatonin secretion because of their chronic interruption in circadian rhythm.

• Advances in technology have improved disease diagnosis during one's life; therefore, one expects a reduction in new diagnosis at autopsy. However, this has not happened. More importantly, rates of autopsy have declined dramatically since the 1960s. This threatens the quality assessment of medical practice.

• In the last decade the life expectancy of cancer patients has increased, but they face many physical, emotional, and social problems. To identify these problems and to improve the quality-of-life of cancer survivors the National Cancer Institute has initiated a new research.

• Sentinel lymph node is the first lymph node that receives lymphatic drainage from the tumor. Cancer cell then travel to other parts via this route. Infiltration of cancer cells in lymph nodes is an important prognostic factor. In breast cancer the axillary node dissection is an widely accepted method to determine the extent of metastases and this also helps to decide the type of adjuvant therapy needed. Because axillary node dissection is an invasive procedure and carries surgical complications, sentinel node biopsy is being tested to determine the stage of the disease.

• In the last three decades, Tamoxifen has earned the reputation of a well tolerated and efficient antiestrogen. From a humble start as an antifertility and "morning after" pill (which failed), it has become a widely prescribed drug in the treatment of breast cancer after surgery and/or radiation therapy, as adjuvant in various treatment combinations and in recent years, in a multinational, large-scale trial for the prevention of breast cancer. While the merit of Tamoxifen in the treatment of an established malignancy is unquestionable, the so far inconsistent results from prevention trials require careful evaluation. We know too little and it is too soon to draw final conclusions.

Glossary

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