Lack of correlation between numbers of circulating t(14;18)-positive cells and response to first-line treatment in follicular lymphoma.

Item does not contain fulltextIn follicular lymphoma, the t(14;18) status of the peripheral blood and bone marrow analyzed by polymerase chain reaction (PCR) is assumed to correlate with disease activity in patients with relapsed disease. The clinical significance of quantitating circulating lymphoma cells by real-time PCR is reported in patients on first-line treatment. Thirty-four consecutive patients with previously untreated follicular lymphoma and detectable t(14;18)-positive cells in pretreatment peripheral blood samples were monitored. All patients were treated with standard chemotherapy in combination with interferon alfa-2b. Before and after induction therapy, blood samples were taken for quantitative analysis of t(14;18). At presentation, a median of 262 t(14;18)-positive cells per 75,000 normal cells was found (range, 1-75 000). Patients with lower numbers of circulating tumor cells more frequently had bulky disease (P =.02). Seventy-nine percent of the patients responded clinically to treatment. In 22 of 28 patients, including 4 patients in whom treatment had failed clinically, the number of circulating t(14;18)-positive cells decreased to undetectable or low levels after therapy. In the remaining responding patients, circulating tumor cells persisted after therapy. These quantitative data on circulating t(14;18)-positive cells call into question the usefulness of molecular monitoring of the blood in a group of patients with follicular lymphoma uniformly treated with a noncurative first-line regimen. T(14;18)-positive cells decreased in peripheral blood after treatment, irrespective of the clinical response. Therefore, the significance of so-called molecular remission should be reconsidered in follicular lymphoma. (Blood. 2001;98:940-944

Transcription of the MAGE-1 gene and the methylation status of its Ets binding promoter elements: a quantitative analysis in melanoma cell lines using a real-time polymerase chain reaction technique

The human MAGE gene family comprises at least 12 highly homologous genes. This makes it very difficult to assess expression of a single member quantitatively by means of Northern blotting. In order to investigate expression of the MAGE-1 gene quantitatively we therefore used the recently developed real-time polymerase chain reaction (PCR), a novel fluorescence-based quantitative PCR technique. This powerful technique enables detection of expression levels which differ by as much as a factor of 10(5) in magnitude. MAGE-1 expression is known to correlate with demethylated status of the Ets binding sites of its promoter. In a panel of 19 melanoma and nine non-melanoma cell lines we were able to confirm the relationship between MAGE-1 expression and demethylation of the Ets binding promoter region. Five cell lines, however, showed only very slight expression, while the two essential Ets promoter elements were largely demethylated. Earlier studies have shown that treatment of MAGE-1-negative cell lines with the demethylating agent 5-aza-2'-deoxycytidine (DAC) is sufficient to induce MAGE-1 expression. We were able to induce clear MAGE-1 expression in two of the non-expressing cell lines by incubation with DAC, although this expression did not reach very high levels. Consistent with this low level of induction is the observation that the Ets binding sites of the MAGE-1 promoter were not completely demethylated in the DAC-treated cell populations. In conclusion, we show in this study that the real-time PCR technique is a very useful tool for the quantification of expression of highly homologous genes. (C) 1999 Lippincott Williams & Wilkins