Genetic Alteration and Cancer

Genetic Alteration and Cancer

Introduction

As with any test, there are caveats, and a poor understanding of these may lead to misuse of the test, false reassurance and consequent under diagnosis of cancer, or false positives and over the investigation of patients. A recent hospital audit concluded that 90 per cent of requests for tumour markers were inappropriate, resulting in about pounds 250,000 of wasted healthcare expenditure per year.1 Given the pressure on GPs to refer less, prescribe less and request fewer investigations, the need to use tests appropriately has never been greater

In addition to this, a number of studies noted it is prospective as a capable marker Studies note that marker's high specificity along with its sensitivity in more than 67 cases of ovarian cancer, attaining levels of 90 percent and 77.6 percent. In contrast with Cancer Antigen 125, SMRP, osteopontin and CA72-4, Human Epididymis Protein 4 acquire the maximum sensitivity in identifying ovarian cancer of the initial stage (Rodriguez et al, 1994).

The researchers said the drugs also were found to take aim at a small but dangerous subpopulation of self-renewing cells, sometimes referred to as cancer stem cells, which evade most cancer drugs and cause recurrence and spread. In a report the issue of Cancer Cell were highlighted, the Johns Hopkins team said their study provides evidence that low doses of the drugs tested on cell cultures cause antitumor responses in breast, lung, and colon cancers. Conventional chemotherapy agents work by indiscriminately poisoning and killing rapidly-dividing cells, including cancer cells, by damaging cellular machinery and DNA (Kinzler and Vogelstein, 1996).

Discussion

Many cancer experts had abandoned AZA and DAC for the treatment of common cancers, according to the researchers, because they are toxic to normal cells at standard high doses, and there was little research showing how they might work for cancer in general. Baylin and his colleague Cynthia Zahnow, Ph.D., decided to take another look at the drugs after low doses of the drugs showed a benefit in patients with a pre-leukemic disorder called myelodysplastic syndrome (MDS). Johns Hopkins investigators also showed benefit of low doses of the drugs in tests with a small number of advanced lung cancer patients. This is contrary to the way we usually do things in cancer research," says Baylin, noting that typically, we start in the laboratory and progress to clinical trials. In this case, we saw results in clinical trials that made us go back to the laboratory to figure out how to move the therapy forward." For the research, Baylin and Zahnow's team worked with leukemia, breast, and other cancer cell lines and human tumour samples using the lowest possible doses that were effective against the cancers. In all, the investigators studied six leukemia cell lines, seven leukemia patient samples, three breast cancer cell lines, seven breast tumour samples (including four samples of tumours that had spread to the lung), one lung cancer tumour sample, and one colon cancer tumour sample. The team treated cell lines and tumour cells with low-dose AZA and DAC in culture for three days and allowed the drug-treated cells to rest for a week. Treated cells and tumour samples were ...