Resolving the ancestry of Austronesian-speaking populations

There are two very different interpretations of the prehistory of Island Southeast Asia (ISEA), with genetic evidence invoked in support of both. The “out-of-Taiwan” model proposes a major Late Holocene expansion of Neolithic Austronesian speakers from Taiwan. An alternative, proposing that Late Glacial/postglacial sea-level rises triggered largely autochthonous dispersals, accounts for some otherwise enigmatic genetic patterns, but fails to explain the Austronesian language dispersal. Combining mitochondrial DNA (mtDNA), Y-chromosome and genome-wide data, we performed the most comprehensive analysis of the region to date, obtaining highly consistent results across all three systems and allowing us to reconcile the models. We infer a primarily common ancestry for Taiwan/ISEA populations established before the Neolithic, but also detected clear signals of two minor Late Holocene migrations, probably representing Neolithic input from both Mainland Southeast Asia and South China, via Taiwan. This latter may therefore have mediated the Austronesian language dispersal, implying small-scale migration and language shift rather than large-scale expansion

Imaging marrow cell population change in lymphoma after chemotherapy by FDG-PET scans and its clinical implications

Presentation no. 1023BPurpose: It is common to see the pattern of diffusely increased FDG uptake in normal bone marrow after chemotherapy on FDG-PET scans due to change in hematopoietic cell population. Decreased FDG uptake after chemotherapy is noted in the areas with PET evidence of bone marrow involvement due to reduction in tumor population. The aims were to correlate cell population change with SUV change over bone marrow biopsy (BMBx) sites after chemotherapy using bone marrow histopathology as the gold standard and investigate its potential predictive value for occult bone marrow involvement by malignant lymphoma. Methods: 26 patients (mean age, 58±15y; 13 female, 13 male) with follicular lymphoma (FL) (Grade I, II, III, n=16) or diffuse large B-cell lymphoma (DLBC) (n=10), referred for FDG-PET/CT scan for initial staging and first restaging after chemotherapy, who had BMBx from unilateral or bilateral iliac crest(s) before chemotherapy, were studied retrospectively. The maximal standardized uptake value (SUV) was measured from BMBx site over the same area on both initial staging and restaging FDG-PET/CT scans. The interval changes of SUV were classified as increase or decrease and correlated with BMBx result of positive or negative for bone marrow involvement by lymphoma. Results: 35 BMBx sites in 26 patients were evaluated. 12 of 35 sites were BMBx positive with interval decrease in SUV in 11 of 12 sites (92%). The remaining 23 of 35 sites were BMBx negative with interval increase in SUV in 21 of 23 sites (91%). The correlation between SUV change over the BMBx site before and after chemotherapy and BMBx result was significant (P<0.0001). Among 14 of the 26 patients (FL, n=4; DLBC, n=10) with focal increased FDG uptake (SUV range form 4.3-31.9) in bone marrow indicating involvement by lymphoma on initial staging scans, all (100%) showed significant interval decreased SUV after chemotherapy. Conclusions: This study demonstrates a strong correlation between marrow metabolic changes (as determined by FDG PET) after chemotherapy with marrow cell population change. This may provide a retrospective means of predicting occult marrow involvement and may help in deciding to deliver more extended therapy during management of lymphoma patients

Exceptionally low metabolic activity in aggressive peripheral T-cell lymphoma

PURPOSE: To investigate metabolic behavior of aggressive peripheral T-cell (PTC) lymphoma compared with other aggressive T-cell (OTC) nonHodgkin's lymphomas (NHLs) and the various grades (1, 2, 3) of follicular B-cell (FC) NHL as a reference cell type for indolent to aggressive behavior. MATERIALS AND METHODS: Pretreatment 2-deoxy-2-[(1)F] fluoro-d-glucose positron emission tomography-computed tomography scans of 33 patients with pathologic diagnosis of aggressive T-cell NHL and FC (FC1 = 6, FC2 = 8, FC3 = 9, PTC = 6, OTC = 4) were analyzed. The maximal standardized uptake value (SUV) was measured over biopsy region (BxSUV) and the highest tumor activity of the body (BmSUV). RESULTS: There were significant differences in both BxSUV (P = 0.036) and BmSUV (P = 0.026) among these five groups with significantly lower metabolic activity in PTC compared with other aggressive NHL (FC3, OTC). BmSUV in PTC was significantly lower than that in OTC (8.2 +/- 2.5 vs. 22.3 +/- 7.0, P = 0.029) and was similar to that of FC1 (9.4 +/- 1.9) and FC2 (9.7 +/- 1.4) but lower than that of FC3 (14.6 +/- 2.7). Similar findings were noted in BxSUV between PTC and OTC (6.7 +/- 2.5 vs. 20.4 +/- 7.2, P = 0.035). CONCLUSION: Although 2-deoxy-2-[(1)F]fluoro-d-glucose positron emission tomography has been found to reflect metabolic activity for the aggressiveness of B-cell NHL, PTC has an exceptionally low metabolic activity, similar to that of low-grade B-cell FC1 and FC2.link_to_subscribed_fulltex

Metabolic phenotypes of lymphomas relate to the rates of treatment response

Presentation no. 1002AObjectives : To investigate the relationship of metabolic phenotype measured by staging PET and the time interval for first metabolic remission of lymphomas. Methods : 66 patients with newly diagnosed non-Hodgkin’s lymphoma (NHL) and Hodgkin’s disease (HD) but without diabetes and other malignancies who had F-18 FDG PET scan performed within 3 months of biopsy were included. Lymphomas were classified using the WHO criteria and graded by the metabolic activity of initial staging PET using maximum standard uptake value (SUV) over the area of biopsy. Cox regression was performed for the duration of post-treatment PET against status of negative PET (otherwise censored) with age, sex, pathologic grade and SUV from staging pre-treatment PET as covariates. Kaplan Meier analysis of the probability of the interval for first negative post-treatment PET was performed in patients with a best discriminating SUV. All PET scans were obtained one hour after injection of 370 MBq F-18 FDG after the patients fasted about 4 hours using a dedicated whole body PET scans. Results : The mean interval of the first post-treatment PET was performed after a duration of 198+/-153 days of the first staging PET scan. Cox regression analysis suggested that SUV=7.5 stratified the differences in the probability in the interval of the first metabolic remission or negative post-treatment PET. Using this cut-off value SUV, there was a difference in the remission interval as revealed by the first negative PET scans among various lymphomas (p=0.02). Conclusions : Results suggest that high metabolic phenotype lymphomas by initial staging PET would respond more quickly to treatment as measured by post-treatment PET than those with low metabolic phenotype lymphomas. As there is a high rate of recurrence in NHL, this may impact decision for the follow up interval of lymphomas.link_to_OA_fulltex