Clinical significance of fragile histidine triad gene expression in adult acute lymphoblastic leukemia.

The FHIT (fragile histidine triad) gene, which is located on 3p14.2 and believed to be a tumor suppressor gene, has been reported to lose its expression in several solid tumors and hematologic malignancies, including acute lymphoblastic leukemia (ALL). The clinical relevance of the loss of FHIT expression in ALL is not known. We used western blot and solid-phase radioimmunoassay (RIA) to analyze Fhit protein expression in 90 patients with ALL. Eighteen (20%) of the tested patients had severely reduced Fhit protein (undetectable by western blot), and 43 patients (47%) had levels lower than those detected in normal bone marrows. Interestingly, seven patients (8%) expressed very high levels (>two-fold the level detected in normal bone marrow). A parallel pattern of FHIT RNA expression was also observed. Of the 90 patients, 39 received induction therapy consisting of hyper-CVAD (hyperfractionated cyclophosphamide, vencristine, adriamycine, and dexamethasone) and were followed in our institution. Patients with low Fhit protein levels showed no statistically significant difference in survival or complete remission duration (CRD) from patients with normal levels (P=0.12 and 0.24, respectively). Our study confirms that FHIT is aberrantly expressed in ALL, but suggests it does not have a role as a prognostic factor. Studies with large numbers of patients and evaluation of the mechanisms of FHIT function in ALL are needed.

Comparison of outcome in acute myelogenous leukemia patients with translocation (8;21) found by standard cytogenetic analysis and patients with AML1/ETO fusion transcript found only by PCR testing.

Patients with normal-karyotype acute myelogenous leukemia (NKAML) may have undetected genetic abnormalities that could affect prognosis. Screening for known AML-specific genetic abnormalities using the reverse transcription polymerase chain reaction (RT-PCR) may help in arriving at a more definitive prognosis. To test this hypothesis, 104 patients without translocation (8;21) and inversion(16), as shown by standard cytogenetic (SC) analysis, were screened for these two genetic abnormalities using RT-PCR. Western blot analysis for the AML1/ETO fusion protein and fluorescent in situ hybridization (FISH) analysis for t(8;21) were performed in patients for whom we had samples. The characteristics and outcome after high-dose cytarabine containing treatments in five patients with t(8;21) shown by RT-PCR alone were then compared to 21 patients with t(8;21) detected using SC analysis. Eight of the 104 patients had masked t(8;21) and none had masked inv(16), as shown by RT-PCR. Five of 54 patients with NKAML had a detectable AML1/ETO fusion RNA transcript. Western blot analysis showed the AML1/ETO fusion protein in four of the seven patients for whom we had samples among the eight with masked t(8;21) shown by RT-PCR. All patients with t(8;21) shown by RT-PCR had negative FISH results. Ninety percent (n=19) of the patients with t(8;21) shown by SC analysis and 40% (n= 2) of the patients with t(8;21) shown by RT-PCR alone achieved a complete remission (P value 0.03). These data suggest that the outcome of NKAML patients with t(8;21) shown by RT-PCR is not equivalent to patients with t(8;21) by SC studies.

Loss of heterozygosity on chromosome 5 in adults with acute lymphoblastic leukemia.

Cytogenetic abnormalities are among the most important pretreatment predictors of outcome in patients with acute lymphoblastic leukemia (ALL). Deletions of genetic material can result in loss of tumor suppressor genes or other translation products that are crucial in maintaining an orderly cell cycle sequence or viability of the apoptotic cascade. Chromosome 5 contains many genes that are relevant in hematopoiesis. Deletions of chromosome 5 or parts thereof are found frequently in myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML) where they are associated with a poor prognosis. Although abnormalities of chromosome 5 are not commonly detected by cytogenetic analysis in patients with acute lymphoblastic leukemias, we hypothesized that loss of heterozygosity (LOH) of microsatellite markers on chromosome 5 may occur more frequently and likewise influence outcome in these patients. Therefore, we analyzed peripheral blood and bone marrow samples of 41 adults with a diagnosis of ALL for LOH by polymerase chain reaction (PCR) and correlated our findings with overall survival of patients with and without LOH. LOH for at least one microsatellite marker was found in seven of 41 patients (17%). All patients demonstrated LOH on the long arm of chromosome 5. In three patients, LOH was extended to 5p. A region of minimal deletion which overlapped in all seven patients could be localized between markers D5S410 and D5S436 corresponding to chromosomal location 5q31-33 which is similar to the area of minimal deletion seen in AML. None of these patients showed involvement of chromosome 5 by cytogenetic analysis. We conclude that patients with ALL have LOH for gene segments on chromosome 5, especially 5q, more frequently than expected from cytogenetic studies. Although, unlike AML, no significant impact on prognosis could be found between patients with and without LOH on chromosome 5. The current data suggest that 5q abnormalities are not specific for AML and can also occur in patients with ALL.

Angiogenesis in acute and chronic leukemias and myelodysplastic syndromes.

Angiogenesis has been associated with the growth, dissemination, and metastasis of solid tumors. The aims of this study were to evaluate the vascularity and the levels of angiogenic factors in patients with acute and chronic leukemias and myelodysplastic syndromes (MDS). The numbers of blood vessels were measured in 145 bone marrow biopsies and the levels of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), tumor necrosis growth factor-alpha (TNF-alpha), tumor growth factor-alpha (TGF-alpha), and hepatocyte growth factor (HGF) were determined in 417 plasma samples. Except for chronic lymphocytic leukemia (CLL), vascularity was significantly higher in all leukemias and MDS compared with control bone marrows. The highest number of blood vessels and largest vascular area were found in chronic myeloid leukemia (CML). VEGF, bFGF, and HGF plasma levels were significantly increased in acute myeloid leukemia (AML), CML, CLL, chronic myelomonocytic leukemia (CMML), and MDS. HGF, TNF-alpha, and bFGF but not VEGF were significantly increased in acute lymphoblastic leukemia (ALL). TNF-alpha levels were significantly increased in all diseases except for AML and MDS. No significant increase was found in TGF-alpha in any leukemia or MDS. The highest plasma levels of VEGF were in CML, and the highest plasma levels of bFGF were in CLL. The levels of HGF were highest in CMML. These data suggest that vascularity and angiogenic factors are increased in leukemias and MDS and may play a role in the leukemogenic process.

Clinical relevance of intracellular vascular endothelial growth factor levels in B-cell chronic lymphocytic leukemia.

Strong evidence exists for an association between high vascular endothelial growth factor (VEGF) levels and poor prognoses in patients with solid tumors and acute leukemia. Using Western blot analysis and solid-phase radioimmunoassay, we measured cellular VEGF levels in B-cell chronic lymphocytic leukemia (CLL) samples from 225 patients and correlated these levels with disease characteristics and prognoses. The median VEGF level in CLL samples was 7.26 times the median level detected in normal peripheral blood mononuclear cells. Patients with lower levels of VEGF protein showed a trend toward shorter survival (P =.07). However, in a subgroup of CLL patients with good prognoses or early-stage disease (Rai stages 0-II, Binet stages A,B; beta2-M

Deletions in the 13q14 locus in adult lymphoblastic leukemia: rate of incidence and relevance.

BACKGROUND: A putative tumor suppressor gene involved in chronic lymphocytic leukemia (CLL) has been localized to the 13q14 locus. Microsatellite analysis was used to test whether this locus also is involved in acute lymphoblastic leukemia (ALL) and its prognostic relevance determined. METHODS: The authors analyzed 49 patients with adult ALL for deletions at the 13q14 locus using a battery of 6 microsatellite markers corresponding to this region (D13S260, STR257, D13S263, D13S153, D13S319, and AFMa301wb5). RESULTS: Five of the 49 adult ALL patients analyzed (10%) showed loss of heterozygosity (LOH) or deletions at 13q14. Similar to CLL, the significant minimal deletions appeared to be localized between D13S260 and AFMa301wb5 and did not involve the retinoblastoma or BRCA2 genes. Among newly diagnosed patients, LOH was associated with shorter survival (P = 0.007). CONCLUSIONS: These data suggest that the 13q14 gene, commonly deleted in CLL patients, also is deleted in some patients with adult ALL. Although the number of the cases in the current study is small, 13q deletions in ALL patients may play a role in the clinical behavior of this disease.

Cellular vascular endothelial growth factor is a predictor of outcome in patients with acute myeloid leukemia.

Vascular endothelial growth factor (VEGF) is a potent mitogen for vascular endothelial cells. It has been associated with angiogenesis, growth, dissemination, metastasis, and poor outcome in solid tumors. To assess cellular VEGF levels and their prognostic significance in newly diagnosed acute myeloid leukemia (AML), we used a radioimmunoassay (RIA) to quantify VEGF levels in stored samples obtained before treatment from 99 patients with newly diagnosed AML treated at the MD Anderson Cancer Center from 1996 to 1998. Outcome in the 99 patients was representative of that observed in all patients seen at this institution with this diagnosis during these years, but the 99 patients had higher white blood cell (WBC) and blast counts than the other patients. Results of the RIA were confirmed by Western blot. There was a relationship between increasing VEGF levels and shorter survival (P =.01), as well as shorter disease-free survival, both from start of treatment and from complete response (CR) date. In contrast, there was no relationship between VEGF level and WBC or blast count, or between VEGF level and such established prognostic factors as age, cytogenetics, performance status, or presence of an antecedent hematologic disorder, and multivariate analysis indicated that VEGF was still prognostic for the above outcomes after accounting for these factors, as well as treatment. Our results suggest that at least in AML patients with higher WBC and blast counts, cellular VEGF level is an independent predictor of outcome.