A first analysis of time trends in cancer mortality in China at the national level is presented. Using a joinpoint regression model, based on data from a national mortality routine reporting system in China (CHIS), time trends in mortality for 9 major cancers are analyzed. Between 1987 and 1999, the age-standardized mortality rates for all cancers combined declined slightly in rural areas but have increased since 1996 in urban areas. The mortality rates for cancers in oesophagus, stomach, cervix uteri, leukaemia (except for urban males after 1996) and nasopharynx declined, while lung cancer and female breast cancer showed significant increasing trends in both urban and rural areas and for both sexes. Cancers of the colon-rectum and liver had different trends in mortality in urban and rural populations. The trends in agespecific mortality rates suggest some different trends in the younger population, which may presage future overall trends, for example, increasing mortality from cancer of the cervix. The observed trends primarily reflect the dramatic changes in socioeconomic circumstances and lifestyles in China in the last 2 decades. Tobacco smoking remains a major problem, with increases in mortality from lung cancer. The improvements in socioeconomic status, diet and nutrition may be responsible for the declining risk of some cancers (oesophagus, stomach and nasopharynx), while increasing the risk for others (breast and colon-rectum). Screening programs (especially for cervix cancer), and more available and better facilities for cancer therapy, may have helped to reduce mortality for several cancers. The large increases in the absolute number of deaths that resulted from the increasing and aging population are much more important in determining the future cancer burden than any changes due to change in risk, emphasizing the increasing importance of cancer as a health problem in the 21st century in China.

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Bone metastasis of breast cancer makes patients suffer from pain, fractures, spinal cord compression, and hypercalcemia, and is almost incurable. Although the mechanisms of bone metastasis in breast cancers have been studied intensively, novel specific target will be helpful to the development of new therapeutic strategy of breast cancer. Herein, we focused on the microRNA of tumor cell‐derived exosomes to investigate the communication between the bone microenvironment and tumor cells. The expression of miR‐20a‐5p in the primary murine bone marrow macrophages (BMMs), MCF‐10A, MCF‐7, and MDA‐MB‐231 cell lines, as well as the cell‐derived exosomes were assessed by qRT‐PCR. Transwell assays were used to evaluate the effects of miR‐20a‐5p on tumor cell migration and invasion. The expression of exosomes marker including CD63and TSG101 was detected by Western Blot. Cell cycle distribution of BMMs was analyzed by flow cytometry. 3‐UTR luciferase reporter assays were used to validate the putative binding between miR‐20a‐5p and SRCIN1. MiR‐20a‐5p was highly expressed in breast tumor tissues and the exosomes of MDA‐MB‐231 cells. MiR‐20a‐5p promoted migration and invasion in MDA‐MB‐231 cells, and the proliferation and differentiation of osteoclasts. MDA‐MB‐231 cell‐derived exosomes transferred miR‐20a‐5p to BMMs and facilitated the osteoclastogenesis via targeting SRCIN1. The present work provides evidence that miR‐20a‐5p transferred from breast cancer cell‐derived exosomes promotes the proliferation and differentiation of osteoclasts by targeting SRCIN1, providing scientific foundations for the development of exosome or miR‐20a‐5p targeted therapeutic intervention in breast cancer progression.

A series of gallia‐supported Pd‐Ga catalysts that consist of metallic nanoparticles on three porous polymorphs of Ga2O3 (α‐, β‐, and γ‐Ga2O3) were synthesized by a controlled co‐precipitation of Pd and Ga. The effects of formation of Ga‐Pd intermetallic compounds (IMCs) were studied in four catalytic reactions: methanol steam reforming, hydrogenation of acetylene, and methanol synthesis by CO and CO2 hydrogenation reactions. The IMC Pd2Ga forms upon reduction of α‐ and β‐Ga2O3‐supported materials in hydrogen at temperatures of 250 and 310 °C, respectively. At higher temperatures, Ga‐enrichment of the intermetallic particles is observed, leading to formation of Pd5Ga3 before the support itself is reduced at temperatures above 565 °C. In the case of Ga‐Pd/γ‐Ga2O3, no information about the metal particles could be obtained owing to their very small size and high dispersion; however, the catalytic results suggest that the IMC Pd2Ga also forms in this sample. Pd2Ga/gallia samples show a stable selectivity towards ethylene in acetylene hydrogenation (≈75 %), which is higher than for a monometallic Pd reference catalyst. An even higher selectivity of 80 % was observed for Pd5Ga3 supported on α‐Ga2O3. In methanol steam reforming, the Ga‐Pd/Gallia catalysts showed, in contrast to Pd/Al2O3, selectivity towards CO2 of up to 40 %. However, higher selectivities, which have been reported for Pd2Ga in literature, could not be reproduced in this study, which might be a result of particle size effects. The initially higher selectivity of the Pd5Ga3‐containing samples was not stable, suggesting superior catalytic properties for this IMC, but that re‐oxidation of Ga species and formation of Pd2Ga occurs under reaction conditions. In methanol synthesis, CO hydrogenation did not occur, but a considerable methanol yield from a CO2/H2 feed was observed for Pd2Ga/α‐Ga2O3.