HTLV-1-infected CD4+ T-cells display alternative exon usages that culminate in adult T-cell leukemia.

BACKGROUND: Reprogramming cellular gene transcription sustains HTLV-1 viral persistence that ultimately leads to the development of adult T-cell leukemia/lymphoma (ATLL). We hypothesized that besides these quantitative transcriptional effects, HTLV-1 qualitatively modifies the pattern of cellular gene expression. RESULTS: Exon expression analysis shows that patients' untransformed and malignant HTLV-1(+) CD4(+) T-cells exhibit multiple alternate exon usage (AEU) events. These affect either transcriptionally modified or unmodified genes, culminate in ATLL, and unveil new functional pathways involved in cancer and cell cycle. Unsupervised hierarchical clustering of array data permitted to isolate exon expression patterns of 3977 exons that discriminate uninfected, infected, and transformed CD4(+) T-cells. Furthermore, untransformed infected CD4+ clones and ATLL samples shared 486 exon modifications distributed in 320 genes, thereby indicating a role of AEUs in HTLV-1 leukemogenesis. Exposing cells to splicing modulators revealed that Sudemycin E reduces cell viability of HTLV-1 transformed cells without affecting primary control CD4+ cells and HTLV-1 negative cell lines, suggesting that the huge excess of AEU might provide news targets for treating ATLL. CONCLUSIONS: Taken together, these data reveal that HTLV-1 significantly modifies the structure of cellular transcripts and unmask new putative leukemogenic pathways and possible therapeutic targets.

HTLV-1 positive and negative T cells cloned from infected individuals display telomerase and telomere genes deregulation that predominate in activated but untransformed CD4+ T cells.

Untransformed HTLV-1 positive CD4(+) cells from infected individuals are selected for expressing tax and displaying morphological features consistent with telomere dysfunctions. We show that in resting HTLV-1 positive CD4(+) cells cloned from patients, hTERT expression parallels tax expression and cell cycling. Upon activation, these cells dramatically augment tax expression, whereas their increase in telomerase activity is about 20 times lower than that of their uninfected counterpart. Activated HTLV-1 positive CD4(+) but not uninfected CD4(+) or CD8(+) clones also repress the transcription of TRF1, TPP1, TANK1, POT1, DNA-PKc and Ku80. Both infected and uninfected lymphocytes from infected individuals shared common telomere gene deregulations toward a pattern consistent with premature senescence. ATLL cells displayed the highest telomerase activity (TA) whereas recovered a telomere gene transcriptome close to that of normal CD4(+) cells. In conclusion HTLV-1-dependent telomere modulations seem involved in clonal expansion, immunosuppression, tumor initiation and progression.

Bilateral hilar foci on 18F-FDG PET scan in patients without lung cancer: variables associated with benign and malignant etiology.

UNLABELLED: Bilateral hilar (18)F-FDG-avid foci are often noted on PET studies of patients without lung cancer. This finding may lead to diagnostic uncertainty about the presence of metastatic disease. Our objective was to evaluate features of these foci associated with benign or malignant etiology. METHODS: We performed a retrospective study of patients with cancer with bilateral hilar foci on 1 or 2 sequential (18)F-FDG PET studies between 2002 and 2006. Patients with lung cancer, sarcoidosis, or anthracosis/silicosis were excluded. Variables evaluated were maximum standard uptake values (SUV max), purity (absence of (18)F-FDG-avid foci in nonhilar mediastinal nodes), symmetry (difference between left and right side SUV max), the primary tumor, node size determined by CT, and, in those who participated in 2 studies, stability of uptake over time. The gold standard was histologic diagnosis or long-term clinical follow-up (range, 19-41 mo; mean, 25 mo). RESULTS: Fifty-one patients with the finding of bilateral hilar (18)F-FDG-avid foci underwent a staging-only PET study; 52 scans from an additional set of patients demonstrated this abnormality on at least 1 of 2 sequential studies, the first of which was performed for staging. On univariate analysis, variables associated with malignancy were SUV max (6.6+/-4.1 vs. 3.5+/-1.0 for benign, P<0.001; t test); impurity (P<0.001; chi(2) test), with 79% of impure scans versus 18% of pure scans being malignant; node size determined by CT (P=0.027); and change in uptake between scans 1 and 2 (change in SUV=2.7+/-2.1 vs. 0.73+/-1.1 for benign, P < 0.01; t test). Variables associated with benign etiology were: symmetry (difference between left and right sides=0.57+/-0.54 for benign vs. 1.8+/-1.7 for malignant, P<0.01), purity, and colorectal primary (75% of colorectal were benign vs. 34% of breast, 49% of lymphoma, and 37% of other, P=0.030; chi(2) test). After multivariate analysis, SUV max and purity were found to be independent predictors, with the odds of malignancy increasing by 1.54 (95% confidence interval, 1.16-2.05) for each unit increase in SUV and decreasing by 0.08 (95% confidence interval, 0.03-0.22) if pure. CONCLUSION: In patients with nonlung cancer, in particular colorectal, foci of symmetric and mild uptake limited to the hilar regions that are stable on 2 sequential PET studies despite intervening anticancer therapy are likely related to a benign etiology.

The role of bone scintigraphy in treatment planning, and predicting pain relief after kyphoplasty.

BACKGROUND: The role of whole-body Tc-MDP bone scanning in the management of vertebral compression fractures with kyphoplasty has not been clearly established. OBJECTIVE: To determine the accuracy of bone scanning in patient selection, planning treatment and predicting response to kyphoplasty. METHODS: Retrospective chart reviews were undertaken of all kyphoplasties performed by the same orthopaedic surgeon between June 2000 and June 2004. All patients who underwent plain radiographs (X-ray) of the spine and bone scanning within 4 weeks of treatment were included. Response to treatment was assessed via a questionnaire administered to the patient 3 weeks after intervention and concomitant objective assessment. Response was graded as excellent, intermediate or poor. Each bone scan was reviewed by two nuclear physicians blinded to the initial scan results, level of treatment and therapeutic response. The readers were asked to indicate the level(s) to be treated according to the bone scan findings. Sites of chronic fractures were also recorded. RESULTS: Sixty-six procedures on 60 patients fulfilled the selection criteria. Fifty-three patients were managed by X-ray and bone scanning (A) and seven were managed by X-ray only (B). There was a significant difference in the rates of sub-optimal results between (A) and (B) (11/53 vs. 7/7, P=0.0001). There was also a significant difference in chronic fracture rates between patients with excellent outcome and those with sub-optimal results (3/42 vs. 7/11, P=0.0002). A high rate of incorrect level selection (3/7) was found in (B). In 12 patients (20%) X-ray showed multiple fractures but the bone scanning demonstrated only one level of acute disease. CONCLUSIONS: Bone scanning is an excellent predictor of response to kyphoplasty and decreases the number of vertebrae to be treated as suggested by X-ray. Preoperative bone scanning is recommended to avoid incorrect selection of treatment level. Even when the appropriate level has been selected an incomplete response can be expected if additional chronic fracture is seen on bone scanning. In the event of unexpected incomplete response, re-evaluation with bone scanning may demonstrate new disease amenable to therapy.

Increasing the radiochemical purity of 99mTc sestamibi commercial preparations results in improved sensitivity of dual-phase planar parathyroid scintigraphy.

BACKGROUND: Poor results for dual-phase parathyroid scintigraphy have recently prompted increased use of dual-tracer imaging. We noticed that seminal studies used higher radiochemical purity than provided by current commercial preparations meeting US Pharmacopea (USP) specifications (90% of technetium bound to sestamibi). We surmised that the presence of unbound Tc (non-MIBI tracer) might hamper dual-phase detection that is dependent on rapid wash-out of technetium from thyroid tissue. PURPOSE: To test the hypothesis that reducing non-MIBI tracer will enhance thyroid wash-out and improve sensitivity of dual-phase imaging. METHODS: Starting in April 2003 we decreased the technetium to sestamibi ratio. This resulted in a significant decrease of non-MIBI tracer from 8.1+/-2.2% (SD) (group 1, n = 42) to 3.5+/-1.1% (group 2, n = 47) (P < 0.05 t-test). We performed a retrospective review of 89 patients with primary hyperparathyroidism who underwent imaging and subsequent surgery. The pathological findings served as the 'gold standard'. RESULTS: Scanning detected 21/39 diseased glands (sensitivity=54%) in group 1 patients. In group 2 imaging detected 38/45 diseased glands (sensitivity = 84%). An improvement in sensitivity (P < 0.01) was achieved by modifying the radiopharmaceutical preparation. CONCLUSIONS: Elevated levels of non-MIBI tracer in Tc-MIBI commercial preparations result in persistent thyroid background activity that may interfere with detection of parathyroid pathology. Achieving a higher degree of radiochemical purity (at least 95% bound, 5% impurities) than required by USP may be needed for optimal results. The large variation in sensitivity reported in the literature may be related in part to non-uniform radiopharmaceutical preparation.

Successful thyroid tissue ablation as defined by a negative whole-body scan or an undetectable thyroglobulin: a comparative study.

BACKGROUND: Successful thyroid tissue ablation of patients with well-differentiated thyroid cancer can be defined by a negative whole-body scan (WBS) and/or an undetectable thyroglobulin (Tg). Variables associated with success are poorly understood. Tg measurement, although more sensitive than WBS, has not been firmly established as the sole monitoring method. In a previous study, we retrospectively evaluated the variables associated with scintigraphic success. Ablation dose (AD) was the only variable associated with success (odds ratio (OR): 1.96 per 1.85 GBq increment; 95% confidence interval (CI)=1.11-3.46). OBJECTIVES: (1) To determine if the variables associated with success are the same using Tg. (2) To determine whether Tg measurement can become the sole method for assessing ablation success. METHODS: We performed the analysis using a Tg level <2 ng.ml-1 as a criterion for completed ablation. Data were available from 109 patients. RESULTS: Univariate analysis showed an effect of stage (OR=0.05; 95% CI=0.01-0.23) and female sex (OR=2.8; 95% CI=1.14-6.89). Multivariate analysis demonstrated only stage to be a significant predictor of success. Ablation was successful by both methods in 62/109 patients and it failed by both in 10/109. There were 21 WBS- Tg+ and 16 WBS+ Tg- patients. CONCLUSIONS: Investigation of the variables associated with successful ablation yields different results depending on the definition of success. There was a significant incidence of WBS+ Tg- cases after initial ablation. Until it is firmly established that such patients have a benign course both monitoring methods should be used.

Oral administration of (131)I by semiautomatic pipette to a patient with severe swallowing difficulties: a case report.

As an alternative method of oral administration of (131)I to a patient with quadriplegia and severe swallowing difficulties, we introduced, into the back of the patient's mouth, a 200- micro L laboratory pipette containing 74 MBq (2 mCi) of (131)I-sodium iodide in a 76- micro L aqueous solution and delivered its contents. The procedure was repeated a few days later with a 1,000- micro L laboratory pipette to administer 1.48 GBq (40 mCi) of (131)I-sodium iodide in a 270- micro L aqueous solution. The patient tolerated both procedures well. The pipette permitted accurate measurement of both dosages and complete (greater than 99.9%) delivery of the tracer in a small volume to the back of the patient's mouth, as documented by assay of the empty pipette after use. In patients with swallowing difficulties, use of the pipette constitutes a safe and efficient means to deliver (131)I-sodium iodide by the oral route.

Chromatin redistribution of the DEK oncoprotein represses hTERT transcription in leukemias.

Although numerous factors have been found to modulate hTERT transcription, the mechanism of its repression in certain leukemias remains unknown. We show here that DEK represses hTERT transcription through its enrichment on the hTERT promoter in cells from chronic and acute myeloid leukemias, chronic lymphocytic leukemia, but not acute lymphocytic leukemias where hTERT is overexpressed. We isolated DEK from the hTERT promoter incubated with nuclear extracts derived from fresh acute myelogenous leukemia (AML) cells and from cells expressing Tax, an hTERT repressor encoded by the human T cell leukemia virus type 1. In addition to the recruitment of DEK, the displacement of two potent known hTERT transactivators from the hTERT promoter characterized both AML cells and Tax-expressing cells. Reporter and chromatin immunoprecipitation assays permitted to map the region that supports the repressive effect of DEK on hTERT transcription, which was proportionate to the level of DEK-promoter association but not with the level of DEK expression. Besides hTERT repression, this context of chromatin redistribution of DEK was found to govern about 40% of overall transcriptional modifications, including those of cancer-prone genes. In conclusion, DEK emerges as an hTERT repressor shared by various leukemia subtypes and seems involved in the deregulation of numerous genes associated with leukemogenesis.

Features of large cell transformation of indolent lymphomas as observed on sequential PET/CT.

OBJECTIVE: Detection of large cell transformation (LCT) has been reported with the increasing use of PET/computed tomography (CT) in patients with indolent lymphomas. However, there is little information on PET/CT characteristics, specifically, the distribution of lesion maximum standardized uptake value (SUV(max)) within a patient, or SUV(max) changes before and after LCT. Our objectives were to compare SUV(max) values and distribution between nontransformed and LCT patients; to compare SUV(max) of LCT and nontransformed lesions in patients with documented focal transformation; and to measure the SUV(max) changes in patients before and after LCT. METHODS: Retrospective study of patients with LCT (n=29)compared with nontransformed (n=41), and comparison of LCT and nontransformed lesions within patients and over time. RESULTS: On average, the highest SUV(max) was greater in LCT patients than in nontransformed patients. In addition, there was a wider range of SUV(max) values in the LCT group compared with the nontransformed group (P<0.05). The median ratio of the SUV(max) of 12 LCT to nontransformed biopsy-proven lesions in the same patient was 4.3, P value of less than 0.05 (range 2.6-15.5). In 10 of 12 patients it was greater than or equal to 3. No change in highest SUV(max) and distribution was shown on serial PET in untreated nontransformed patients. CONCLUSION: LCT is often focal and is associated with higher SUV(max) than nontransformed. The emergence of a focus with SUV(max) three times or higher than others on a single scan, or that has tripled or more in value on serial scans, should raise suspicion for LCT.

FDG positron emission tomography/computed tomography scan may identify mantle cell lymphoma patients with unusually favorable outcome.

OBJECTIVE: Patients diagnosed with mantle cell lymphoma (MCL) have generally poor prognosis, but a minority have a longer survival. There are no markers to identify this group and no generally established prognostic index for MCL. Our objective was to assess the prognostic value of the staging FDG PET/computed tomography (CT) scan. METHODS: We retrospectively analyzed initial scans performed at three institutions on biopsy-proven, cyclin D (+) MCL patients. The association of the SUVmax of the 'hottest focus' with overall survival (OS) and failure-free survival (FFS) was evaluated. Receiver operating characteristic analysis of SUVmax versus survival was used to establish a cut-off point of 4.83. In addition, PET findings were compared with contrast-enhanced CT performed within 3 weeks in patients from one institution. RESULTS: Both the OS and FFS for patients with SUVmax greater than 5 were significantly decreased (P<0.01 and <0.001, respectively) as compared with the patients with SUV < or = 5. The 5-year OS for group with SUVmax < or = 5 was 87.7% and for SUVmax greater than 5 it was 34%. For SUVmax < or = 5, the median FFS was 45.3 months as compared with 10.6 months for SUVmax greater than 5. PET changed the stage as compared with CT alone in 45% of patients. CONCLUSION: Staging FDG PET/CT is superior to CT and may be used in the future for identification of a subset of MCL patients with a better outcome than otherwise expected.

Role of fluorine-18 fluoro-deoxyglucose positron emission tomography scan in the evaluation and follow-up of patients with low-grade lymphomas.

BACKGROUND: Fluorine-18 fluoro-deoxyglucose positron emission tomography (FDG-PET) scanning has excellent sensitivity and specificity for staging non-Hodgkin lymphomas, but to the authors' knowledge few studies to date have evaluated FDG-PET in low-grade lymphomas only. METHODS: A retrospective study was performed on patients with biopsy-proven nontransformed and transformed follicular lymphoma (FL), B-cell small-cell lymphocytic lymphoma (SLL/CLL), or marginal zone lymphoma (MZL) who underwent PET and computed tomography (CT) scans within 3 weeks. Standard uptake values (SUV) of all abnormal foci were measured. RESULTS: In FL, PET demonstrated 94% sensitivity and 100% specificity for staging. PET was more specific than CT for detecting recurrence or assessing therapeutic responses (91% vs. 50%). FDG avidity among patients with WHO Grades 1, 2, and 3 disease was not significantly different (analysis of variance [ANOVA]). For MZL staging, PET had moderate sensitivity (71%) and outperformed CT alone in the depiction of extranodal sites (85% vs. 57% sensitivity). In SLL/CLL, PET sensitivity was 53% and underestimated disease extent in 5 of 19 patients (26%) compared with CT. PET did not affect initial management but confirmed suspected recurrences in 75% of patients. Nontransformed FL had a higher SUV (ANOVA, P < .05) compared with MZL and SLL/CLL. SUV was higher in transformed than in nontransformed tumors (P < .001, Student t test). CONCLUSIONS: PET usefulness in staging low-grade lymphomas varies depending on histology. PET sensitivity is excellent in FL and moderate in MZL. PET is more specific than CT for follow-up in all types. PET has limited usefulness for SLL/CLL staging. However, a suggestive pattern of hazy and mild uptake was often noted in positive scans. In all low-grade lymphomas, the emergence of foci of intense uptake should raise suspicion of conversion to high-grade disease.