Dan Corcos

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We have hypothesized that the c-myc oncogene might promote DNA amplification. Resistance to methotrexate (MTX), a widely used cancer chemotherapeutic agent, often results from amplification of the gene coding for the target enzyme, dihydrofolate reductase (DHFR). We report here that gratuitously induced expression of c-myc in rat fibroblasts grown in the(More)
BACKGROUND Heavy-chain diseases (HCDs) are human lymphoproliferative neoplasias that are characterized by the secretion of truncated immunoglobulin heavy chains devoid of light chains. We have previously proposed--by analogy to the process by which mutated growth factor receptors can be oncogenic--that because the genetic defects in HCDs result in the(More)
Neoplastic B cells from H chain disease patients express a truncated B cell receptor (BCR), comprising a membrane Ig that lacks part of its extracellular domain. It has been speculated that deletion of the Ag binding domain would confer a constitutive activity on the BCR, as it has been shown for oncogenic growth factor receptors. A V region-less BCR has(More)
We looked systematically for the presence of receptor like binding sites for 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) in the cytosol from 22 breast cancers. Cytosols were centrifuged on 5-20% sucrose gradients after labeling with tritiated 1,25 (OH)2D3 (3H-1,25(OH)2D3 or 25-hydroxyvitamin D3 (25(OH)D3 alone or in the presence of a large excess of these(More)
Heavy chain diseases (HCD) are neoplastic proliferations of B cells which secrete truncated immunoglobulin heavy chains without associated light chains. These proteins are encoded by mutated genes which may also give rise to truncated membrane immunoglobulins. The neoplastic cells proliferate in vivo although they cannot bind any antigen, due to deletions(More)
Recombining sequence (RS) recombination is a DNA rearrangement that deletes one or two C kappa alleles in a large proportion of lambda-expressing B cells. Since its discovery, this recombination has been suggested to play a role in activating lambda gene rearrangements. A model involving a positive signal generated by RS recombination seems to be excluded,(More)
We have studied the expression of c-fos gene in rat hepatoma induced by DENA. An increase of c-fos mRNA concentration was observed after 8 days, but the maximal 5- to 6-fold increase was observed after 70 weeks. This increase was found in perinodular hepatocytes as well as in cancer nodules. c-fos expression was also enhanced during liver regeneration at a(More)
The activation of N-myc and c-myc genes has been implicated in the genesis of a variety of cancers. In order to determine whether this activation is related to the process of cell growth, we examined N-myc and c-myc expression in rat hepatocytes when growth was stimulated by partial hepatectomy and in rat liver during neoplastic growth induced by(More)
The expression of the c-Ha-ras, the c-Ki-ras and the N-ras genes was measured by the dot blot technique in rat liver tumors induced by a short diethylnitrosamine (DENA) treatment and in the surrounding liver cells. A 2 to 25 times higher level of transcript was found as well in the surrounding cells, as in the tumor cells, as compared to the level in(More)