All patients with chronic myelogenous leukemia (CML) undergo clinical transition from chronic to acute phase. This transition is often associated with deletion of the short arm of chromosome 17 in the form of the i(17q) aberration. Since the p53 gene is a suppressor gene and is located on 17p13, we examined the possibility that it is inactivated during progression of CML. Therefore, we studied the structure and expression of p53 in the leukemic cells of a large number of CML patients in acute phase. We found that although the gene is rarely rearranged, one p53 allele is completely deleted in patients with the i(17q) aberration as well as in some patients who do not show karyotypic changes. In all of these patients the remaining allele is inactivated through loss of expression, rearrangement, or point mutation. Detailed analysis of some patients who carry both p53 alleles indicated neither loss of expression nor structural alterations. It appears that p53 loss of function is associated with progression of around 25% of CML patients.
Primary effusion lymphoma (PEL) is a recently described rare type of non-Hodgkin's lymphoma occurring almost exclusively in HIV infected people. Human herpesvirus 8 (HHV-8), has been linked with PEL, and a causative relationship has been suggested. In the vast majority of PEL cases Epstein-Barr virus (EBV) has been found in the tumour cells. We describe here an elderly human immune deficiency (HIV) seronegative man with intractable chest pain and pleural effusion. The diagnosis of malignant lymphoma was suggested cytologically and confirmed histologically following pleural biopsy. No lymphadenopathy or organ involvement with lymphoma was found. Systemic chemotherapy with a modified CHOP regimen with G-CSF support gradually led to the resolution of the chest pain and ultimately resulted in a complete clinical remission (CCR). The presence of HHV-8 was demonstrated by PCR using paraffin-embedded tissue samples from the involved pleura, whereas EBV-associated genetic material was absent. The patient remained in CCR for 18 months and died of an unrelated cause (cerebrovascular event). Only 11 other cases with clinical and virological features similar to those of our patient have been reported in the literature. Analysis of these rare cases suggests HIV-negative EBV-negative PEL to be a distinct clinical entity with epidemiological features resembling classical KS and supports an EBV-independent role for HHV-8 in the pathogenesis of PEL.
Novel therapeutic regimens containing purine analogs and monoclonal antibodies have led to significant improvement in the course of indolent lymphoproliferative diseases (LPD). Complete clinical and even molecular remissions have been achieved in an increasing proportion of patients. In parallel to their tumor cytotoxic effect, these agents are inevitably associated with prolonged immunosuppression inherent to their mechanism of antilymphocytic activity. Until now, attention has been paid mainly to opportunistic infection occurring as a result of the above drug-induced immunosuppression and less to other possible complications, such as malignancy or tumor progression in the immunocompromised host. Here we briefly report nine patients with previously treated indolent LPD in whom the onset of large-cell transformation occurred during or shortly after the initiation of regimens containing these agents before transformation occurred. One patient had received rituximab alone, three fludarabine-containing regimens and five received sequential regimens containing both agents. This
The major consequence of the formation of the Philadelphia (Ph1) chromosome characteristic of leukemia cells of patients with chronic myelogenous leukemia (CML) is fusion of c-abl and bcr genes. Using a sensitive RNase protection technique, we analyzed mRNA from a large number of CML patients. In most, we identified one or both species of bcr-abl chimeric transcripts. These two mRNAs vary in the specific bcr exon joined to abl exon II and are translated into slightly different proteins. The amounts of the fused mRNA within leukemia cells vary considerably between individuals and do not correlate with the phase of the disease.
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