Prasad Koduru

In vivo measurements document the dynamic cellular kinetics of chronic lymphocytic leukemia B cells

Due to its relatively slow clinical progression, B cell chronic lymphocytic leukemia (B-CLL) is classically described as a disease of accumulation rather than proliferation. However, evidence for various forms of clonal evolution suggests that B-CLL clones may be more dynamic than previously assumed. We used a nonradioactive, stable isotopic labeling method to measure B-CLL cell kinetics in vivo. Nineteen patients drank an aliquot of deuterated water (2H2O) daily for 84 days, and 2H incorporation into the deoxyribose moiety of DNA of newly divided B-CLL cells was measured by gas chromatography/mass spectrometry, during and after the labeling period. Birth rates were calculated from the kinetic profiles. Death rates were defined as the difference between calculated birth and growth rates. These analyses demonstrated that the leukemic cells of each patient had definable and often substantial birth rates, varying from 0.1% to greater than 1.0% of the entire clone per day. Those patients with birth rates greater than 0.35% per day were much more likely to exhibit active or to develop progressive disease than those with lower birth rates Thus, B-CLL is not a static disease that results simply from accumulation of long-lived lymphocytes. Rather, it is a dynamic process composed also of cells that proliferate and die, often at appreciable levels. The extent to which this turnover occurs has not been previously appreciated. A correlation between birth rates and disease activity and progression appears to exist, which may help identify patients at risk for worsening disease in advance of clinical deterioration.

Whole-exome sequencing of pancreatic cancer defines genetic diversity and therapeutic targets.

Pancreatic ductal adenocarcinoma (PDA) has a dismal prognosis and insights into both disease etiology and targeted intervention are needed. A total of 109 micro-dissected PDA cases were subjected to whole-exome sequencing. Microdissection enriches tumour cellularity and enhances mutation calling. Here we show that environmental stress and alterations in DNA repair genes associate with distinct mutation spectra. Copy number alterations target multiple tumour suppressive/oncogenic loci; however, amplification of MYC is uniquely associated with poor outcome and adenosquamous subtype. We identify multiple novel mutated genes in PDA, with select genes harbouring prognostic significance. RBM10 mutations associate with longer survival in spite of histological features of aggressive disease. KRAS mutations are observed in >90% of cases, but codon Q61 alleles are selectively associated with improved survival. Oncogenic BRAF mutations are mutually exclusive with KRAS and define sensitivity to vemurafenib in PDA models. High-frequency alterations in Wnt signalling, chromatin remodelling, Hedgehog signalling, DNA repair and cell cycle processes are observed. Together, these data delineate new genetic diversity of PDA and provide insights into prognostic determinants and therapeutic targets.

EGFR-Mediated Beclin 1 Phosphorylation in Autophagy Suppression, Tumor Progression, and Tumor Chemoresistance

Cell surface growth factor receptors couple environmental cues to the regulation of cytoplasmic homeostatic processes, including autophagy, and aberrant activation of such receptors is a common feature of human malignancies. Here, we defined the molecular basis by which the epidermal growth factor receptor (EGFR) tyrosine kinase regulates autophagy. Active EGFR binds the autophagy protein Beclin 1, leading to its multisite tyrosine phosphorylation, enhanced binding to inhibitors, and decreased Beclin 1-associated VPS34 kinase activity. EGFR tyrosine kinase inhibitor (TKI) therapy disrupts Beclin 1 tyrosine phosphorylation and binding to its inhibitors and restores autophagy in non-small-cell lung carcinoma (NSCLC) cells with a TKI-sensitive EGFR mutation. In NSCLC tumor xenografts, the expression of a tyrosine phosphomimetic Beclin 1 mutant leads to reduced autophagy, enhanced tumor growth, tumor dedifferentiation, and resistance to TKI therapy. Thus, oncogenic receptor tyrosine kinases directly regulate the core autophagy machinery, which may contribute to tumor progression and chemoresistance.

Repetitive Cycles of High-Dose Cytarabine Benefit Patients With Acute Myeloid Leukemia and inv(16)(p13q22) or t(16;16)(p13;q22): Results from CALGB 8461

PURPOSE To study the impact of repetitive (three to four courses) versus a single course of high-dose cytarabine (HDAC) consolidation therapy on outcome of patients with acute myeloid leukemia (AML) and inv(16)(p13q22) or t(16;16)(p13;q22). PATIENTS AND METHODS We examined the cumulative incidence of relapse (CIR), relapse-free survival (RFS), and overall survival (OS) for 48 adults younger than 60 years with inv(16)/t(16;16) who had attained a complete remission on one of four consecutive clinical trials and were assigned to receive HDAC consolidation therapy. Twenty-eight patients were assigned to either three or four courses of HDAC, and 20 patients were assigned to one course of HDAC followed by alternative intensive consolidation therapy. RESULTS Pretreatment features were similar for the two groups. The CIR was significantly decreased in patients assigned to receive three to four cycles of HDAC compared with patients assigned to one course (P=.03; 5-year CIR, 43% v 70%, respectively). The difference in RFS also approached statistical significance (P=.06). In a multivariable analysis that adjusted for potential confounding covariates, only treatment assignment (three to four cycles of HDAC) predicted for superior RFS (P=.02). The OS of both groups was similar (P=.93; 5-year OS, 75% for the three to four cycles of HDAC group v 70% for the one cycle of HDAC group), reflecting a high success rate with stem-cell transplantation salvage treatment administered among patients in both treatment groups. CONCLUSION We conclude that, in AML patients with inv(16)/t(16;16), repetitive HDAC therapy decreases the likelihood of relapse compared with consolidation regimens including less HDAC.

Outcome of Induction and Postremission Therapy in Younger Adults With Acute Myeloid Leukemia With Normal Karyotype: A Cancer and Leukemia Group B Study

PURPOSE Evaluate the outcome of induction and postremission therapy in adults younger than 60 years with normal cytogenetics acute myeloid leukemia (AML). PATIENTS AND METHODS In 490 patients, induction included cytarabine and daunorubicin (AD) or cytarabine and escalated doses of daunorubicin and etoposide +/- PSC-833 (ADE/ADEP). Intensification included one cycle of high-dose cytarabine (HDAC) followed by etoposide/cyclophosphamide and mitoxantrone/diaziquone (group I), three HDAC cycles (group II), four intermediate-dose cytarabine (IDAC) or HDAC cycles (group III), or one HDAC/etoposide cycle and autologous stem-cell transplantation (ASCT; group IV). RESULTS Of 350 patients receiving AD, 73% achieved complete remission (CR), compared with 82% of 140 receiving ADE/ADEP (P = .04). Splenomegaly was associated with a lower CR rate (P < .001), and ADE/ADEP, with a higher CR rate in younger patients (P = .005). The 5-year disease-free survival (DFS) rate was 28% each for intensification groups I and II, compared with 41% and 45% for groups III and IV, respectively (P = .02). The 5-year cumulative incidence of relapse (CIR) was 62% and 67% for groups I and II, respectively, compared with 54% and 44% for groups III and IV, respectively (P = .049). The type of postremission intensification remained significant for DFS and CIR in multivariable analysis. CONCLUSION In younger adults with normal cytogenetics AML, splenomegaly predicts a lower CR rate, and the postremission strategies of either four cycles of I/HDAC or one cycle of HDAC/etoposide followed by ASCT are associated with improved DFS and reduced relapse compared with therapies that include fewer cycles of cytarabine or no transplantation.

Comparison of Cytogenetic and Molecular Genetic Detection of t(8;21) and inv(16) in a Prospective Series of Adults With De Novo Acute Myeloid Leukemia: A Cancer and Leukemia Group B Study

PURPOSE To prospectively compare cytogenetics and reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of t(8;21)(q22;q22) and inv(16)(p13q22)/t(16;16)(p13;q22), aberrations characteristic of core-binding factor (CBF) acute myeloid leukemia (AML), in 284 adults newly diagnosed with primary AML. PATIENTS AND METHODS Cytogenetic analyses were performed at local laboratories, with results reviewed centrally. RT-PCR for AML1/ETO and CBFbeta/MYH11 was performed centrally. RESULTS CBF AML was ultimately identified in 48 patients: 21 had t(8;21) or its variant and AML1/ETO, and 27 had inv(16)/t(16;16), CBFbeta/MYH11, or both. Initial cytogenetic and RT-PCR analyses correctly classified 95.7% and 96.1% of patients, respectively (P =.83). Initial cytogenetic results were considered to be false-negative in three AML1/ETO-positive patients with unique variants of t(8;21), and in three CBFbeta/MYH11-positive patients with, respectively, an isolated +22; del(16)(q22),+22; and a normal karyotype. The latter three patients were later confirmed to have inv(16)/t(16;16) cytogenetically. Only one of 124 patients reported initially as cytogenetically normal was ultimately RT-PCR-positive. There was no false-positive cytogenetic result. Initial RT-PCR was falsely negative in two patients with inv(16) and falsely positive for AML1/ETO in two and for CBFbeta/MYH11 in another two patients. Two patients with del(16)(q22) were found to be CBFbeta/MYH11-negative. M4Eo marrow morphology was a good predictor of the presence of inv(16)/t(16;16). CONCLUSION Patients with t(8;21) or inv(16) can be successfully identified in prospective multi-institutional clinical trials. Both cytogenetics and RT-PCR detect most such patients, although each method has limitations. RT-PCR is required when the cytogenetic study fails; it is also required to determine whether patients with suspected variants of t(8;21), del(16)(q22), or +22 represent CBF AML. RT-PCR should not replace cytogenetics and should not be used as the only diagnostic test for detection of CBF AML because of the possibility of obtaining false-positive or false-negative results.

Acute agranular CD4-positive natural killer cell leukemia. Comprehensive clinicopathologic studies including virologic and in vitro culture with inducing agents

Background. A 63‐year‐old male presented with fever, a subcutaneous nodule, gingival hypertrophy, lacrimal gland enlargement, and no lymphadenopathy or hepatosplenomegaly, but had anemia, thrombocytopenia, and peripheral blood (PB) plus bone marrow (BM) involvement by leukemic cells. There was minimal response to multiagent chemotherapy and local radiotherapy, with a survival of 6.5 months from disease diagnosis.

18q21 rearrangement in diffuse large cell lymphoma: incidence and clinical significance

Summary. Cytogenetic, molecular genetic and clinical information was collected for 102 cases of diffuse large cell lymphoma (DLCL) ascertained in a diagnostic laboratory over a 3‐year period. Nineteen cases showed evidence of either a t(14;18) or a rearrangement of one of three genomic probes for breakpoints at 18q21. Clinical and histologic evidence of transformation from follicular lymphoma or chronic lymphocytic leukaemia was available in six cases. Except for age, prognostic clinical variables (LDH, stage, extranodal involvement) were similar between the 18q21 rearranged patients and DLCL patients without 18q21 rearrangement. At a median follow‐up in excess of 2 years for both groups, there was no difference in overall survival between the 18q21 rearranged group compared to DLCL patients lacking this genetic abnormality. The median disease‐free survival for the 18q21 rearranged group, however, was significantly shorter and survival in partial remission longer. The propensity for extended survival of the 18q21 rearranged DLCL patients with residual or recurrent disease resembled the clinical behaviour of nodular lymphoma patients with t(14;18). These results suggest that cytogenic or molecular genetic identification of a chromosome 18q21 translocation may be of prognostic significance in the analysis of treatment protocols for patients with DLCL.

Abnormal Cytogenetics at Date of Morphologic Complete Remission Predicts Short Overall and Disease-Free Survival, and Higher Relapse Rate in Adult Acute Myeloid Leukemia: Results From Cancer and Leukemia Group B Study 8461

PURPOSE As most patients with acute myeloid leukemia (AML) with morphologic complete remission (CR) ultimately relapse, better predictors for outcome are needed. Recently, Cheson et al suggested using cytogenetic remission (CRc) as part of the criteria for CR. To our knowledge, ours is the first relatively large study evaluating the usefulness of CRc attained immediately following induction chemotherapy. PATIENTS AND METHODS We included AML patients treated on Cancer and Leukemia Group B front-line studies with cytogenetic samples obtained at diagnosis and at the first day of documented CR following induction. Patients with abnormal cytogenetics at diagnosis, and normal cytogenetics at CR (NCR; n = 103) were compared with those with abnormal cytogenetics both at diagnosis and at CR (ACR; n = 15) for overall survival (OS), disease-free survival (DFS), and cumulative incidence of relapse (CIR). Cox proportional hazards models determined the prognostic significance of cytogenetics at CR, adjusting for other covariates. RESULTS Clinical features were similar for both groups, with the exception of favorable cytogenetics [t(8;21), inv(16)/t(16;16), t(15;17)] at diagnosis, which was more frequent (P =.03) in the NCR group. Median follow-up was 3.1 years (range, 1.0 to 11.4 years). ACR patients had significantly shorter OS (P =.006) and DFS (P =.0001), and higher CIR (P =.0001). In multivariable models, the NCR and ACR groups were predictors for OS (P =.03), DFS (P =.02), and CIR (P =.05). The relative risk of relapse or death was 2.1 times higher for ACR patients than for NCR patients (95% CI, 1.1 to 3.9). CONCLUSION Our data suggest that converting to normal karyotype at the time of first CR is an important prognostic indicator and support the use of CRc as a criterion of CR in AML.

Aggressive natural killer cell lymphoma/leukemia: A recently recognized clinicopathologic entity

We report a comprehensive study of a case of aggressive natural killer cell lymphoma/leukemia, which is characterized by young male predominance, rapidly progressive clinical course, and presence of lymphadenopathy, hepatosplenomegaly, and bone marrow involvement. The leukemic phase is frequently preceded by pancytopenia. The diagnostic clues are the detection of cytoplasmic granules in tumor cells on Wright-Giemsa-stained tissue imprints or smears and a selective loss of T-cell antigens. Immunophenotyping is decisive in making the final diagnosis by showing positive natural killer cell markers (CD16, CD56, and/or CD57), CD2, CD11c, and Ia, but negative CD3, T-cell receptor heterodimers, terminal deoxynucleotidyl transferase, and B-cell markers. Genotyping always shows germline configuration in both immunoglobulin and T-cell receptor genes. The unique feature in this case is its presentation as a testicular lymphoma, which has not been previously reported. Polymerase chain reaction was performed in this case but failed to detect human T-cell leukemia virus type I/II provirus. It is important to recognize this new entity as it is a highly aggressive disease with a rapidly progressive clinical course and fails to respond to any chemotherapeutic regimen available.