Objectives: We examined breast density by dual energy X‐ray absorptiometry (DXA) in relation to pubertal maturation and body fatness among girls of several ethnic groups, which may suggest important risk factors for future breast cancer. Methods: Recruiting 113 girls from Kaiser Permanente Hawaii, we determined ethnicity, age at menarche, weight, height; body mass index (BMI), BMI Z‐scores, Tanner breast, and pubic hair pubertal stages (and classified stages for synchrony, thelarche or adrenarche). DXA scans of the whole body provided percent total and segmental body fat; and separate (specially calibrated) breast scans provided breast tissue, total area, and volume (from manual delineation); absolute and percent fibroglandular volume (%FGV, or breast density) were computed. Statistical analysis included correlation, chi‐square tests, ANOVA, and stepwise regression. Results: Twenty‐six percent of girls were overweight or obese. Higher BMI was associated with greater breast area, breast volume, FGV, and with lower breast density (P < 0.0001). Breast area, breast volume, and FGV were positively associated with Tanner breast stage (P < 0.001). Breast density increased until Tanner breast Stage 4 but was lower in Stage 5 (P = 0.03). Pubertal thelarche was associated with lower breast density, compared to synchrony or adrenarche (P = 0.03). Girls with higher BMI (P = 0.02), and Asian girls (compared to White, P = 0.04) were more likely to have pubertal thelarche. Determinants of breast density were, in (stepwise regression) order, percent body fat, achieved menarche, BMI Z‐score, Tanner breast stage (non‐linear), and “Other” ethnicity. Conclusions: Female adolescent breast density was negatively associated with body fatness and positively associated with menarche. Am.J. Hum. Biol. 2011. © 2011 Wiley‐Liss, Inc.

The proto-oncogene c-Kit, a transmembrane receptor tyrosine kinase, is an important regulator of cell growth whose constitutively active oncogenic counterpart, v-kit, induces sarcomas in cats. Mutations in murine c-kit that reduce the receptor tyrosine kinase activity cause deficiencies in the migration and proliferation of melanoblasts, hematopoietic stem cells, and primordial germ cells. We therefore investigated whether c-Kit regulates normal human melanocyte proliferation and plays a role in melanomas. We show that normal human melanocytes respond to mast cell growth factor (MGF), the Kit-ligand that stimulates phosphorylation of tyrosyl residues in c-Kit and induces sequential phosphorylation of tyrosyl residues in several other proteins. One of the phosphorylated intermediates in the signal transduction pathway was identified as an early response kinase (mitogen-activated protein [MAP] kinase). Dephosphorylation of a prominent 180-kDa protein suggests that MGF also activates a phosphotyrosine phosphatase. In contrast, MGF did not induce proliferation, the cascade of protein phosphorylations, or MAP kinase activation in the majority of cells cultured from primary nodular and metastatic melanomas that grow independently of exogenous factors. In the five out of eight human melanoma lines expressing c-kit mRNAs, c-Kit was not constitutively activated. Therefore, although c-Kit-kinase is a potent growth regulator of normal human melanocytes, its activity is not positively associated with malignant transformation.

BACKGROUNDThe erythropoietin‐producing hepatoma amplified sequence (Eph) family is the largest subfamily of receptor tyrosine kinases (RTKs). The Ephs (receptors) bind to specific cell‐bound ligands, called ephrins. The binding of this ligand‐receptor system is dependent on cell‐cell interactions. The ephrin‐Eph system is important in embryologic development and differentiation of the nervous and vascular systems. In the current study, the authors hypothesized that ephrins may play a role in the growth and development of colon carcinoma and may be expressed differentially in normal and malignant colonic tissues.METHODSReverse transcriptase‐polymerase chain reaction (RT‐PCR), Northern Blot analyses, and immunohistochemistry were used to examine 11 colon carcinoma cell lines and 20 human colon carcinoma specimens with adjacent uninvolved mucosa for the expression of EphB and ephrin‐B family members.RESULTSEphB2, EphB3, and EphB4 mRNA expression and ephrin‐B2 mRNA expression was detected in all the cell lines and colon carcinoma specimens examined. Immunohistochemical analysis showed that ephrin‐B2 had higher expression in the colon carcinoma specimens studied than in adjacent normal mucosa. Ephrin‐B2 and EphB4 most frequently were expressed on the luminal surface of colon carcinoma epithelium.CONCLUSIONSThe results of the current suggest that the ephrin‐Bs are expressed differentially in colon carcinoma and normal mucosa specimens and thus may play a role in the progression of colon carcinoma. Further studies are necessary to determine the functional role of ephrin‐Bs in colon carcinoma angiogenesis and growth. Cancer 2002;94:934–9. © 2002 American Cancer Society.DOI 10.1002/cncr.10122

BACKGROUND Angiopoietin‐1 (Ang‐1) and angiopoietin‐2 (Ang‐2) are important regulators of endothelial cell (EC) survival. Current models suggest that an increase in Ang‐2 expression in ECs leads to the initiation of angiogenesis. The authors hypothesized that the imbalance of Ang‐1 and Ang‐2 activities in colon carcinoma leads to a net gain in Ang‐2 function. METHODS Reverse transcriptase‐polymerase chain reaction (RT‐PCR) analyses and immunofluorescent double‐staining were performed to examine human colon carcinoma cell lines, surgical specimens, normal mucosa, and liver metastases for the expression of Ang‐1 and Ang‐2. RESULTS RT‐PCR analyses revealed that 7of 18 colon carcinoma cell lines expressed Ang‐1, and 14 of 18 colon carcinoma cell lines expressed Ang‐2 (P < 0.05). Of the surgical specimens from patients with colon carcinoma, 6 of 11 specimens expressed Ang‐1, and 11 of 11 specimens expressed Ang‐2 (P < 0.05). However, Ang‐1 and Ang‐2 were expressed with relative equal frequency in normal mucosa (P = 0.62). Immunofluorescent staining (n = 20 specimens) revealed the presence of Ang‐2 protein in normal mucosa and tumor epithelium, but Ang‐1 was expressed only in normal mucosa. A similar pattern was found for hepatic colorectal metastases. Double staining for Ang‐1 or Ang‐2 and cytokeratin‐22 (an epithelial marker) demonstrated that Ang‐1 was produced by uninvolved, normal colonic epithelium, whereas Ang‐2 was produced by normal and malignant colonic epithelium. CONCLUSIONS In patients with colon carcinoma, Ang‐2 is expressed ubiquitously in tumor epithelium, whereas expression of Ang‐1 in tumor epithelium is rare. The net gain of Ang‐2 activity is possibly an initiating factor for tumor angiogenesis. Cancer 2001;92:1138–43. © 2001 American Cancer Society.

Background This longitudinal study aims to characterize longitudinal body mass index ( BMI ) trajectories during young adulthood (20–40 years) and examine the impact of level‐independent BMI trajectories on hypertension risk. Methods and Results The cohort consisted of 3271 participants (1712 males and 1559 females) who had BMI and blood pressure ( BP ) repeatedly measured 4 to 11 times during 2004 to 2015 and information on incident hypertension. Four distinct trajectory groups were identified using latent class growth mixture model: low‐stable (n=1497), medium‐increasing (n=1421), high‐increasing (n=291), sharp‐increasing (n=62). Model‐estimated levels and linear slopes of BMI at each age point between ages 20 and 40 were calculated in 1‐year intervals using the latent class growth mixture model parameters and their first derivatives, respectively. Compared with the low‐stable group, the hazard ratios and 95% CI were 2.42 (1.88, 3.11), 4.25 (3.08, 5.87), 11.17 (7.60, 16.41) for the 3 increasing groups, respectively. After adjusting for covariates, the standardized odds ratios and 95% CI of model‐estimated BMI level for incident hypertension increased in 20 to 35 years, ranging from 0.80 (0.72–0.90) to 1.59 (1.44–1.75); then decreased gradually to 1.54 (1.42–1.68). The standardized odds ratio s of level‐adjusted linear slopes increased from 1.22 (1.09–1.37) to 1.79 (1.59–2.01) at 20 to 24 years; then decreased rapidly to 1.12 (0.95–1.32). Conclusions These results indicate that the level‐independent BMI trajectories during young adulthood have significant impact on hypertension risk. Age between 20 and 30 years is a crucial period for incident hypertension, which has implications for early prevention.

The pathogenesis of gastric cancer is not completely understood. Tumor necrosis factor-α-induced protein-8 like-2 (TIPE2) has recently been identified as a novel negative regulator gene of the immune system, and studies in mice and humans have suggested its inhibitory action in both inflammation and cancer. In this study, we examined the expression levels of TIPE2 in human gastric cancer tissues and also samples of paraneoplastic control tissue, and found that TIPE2 expression was reduced in gastric cancer. To investigate the role of TIPE2 in gastric cell carcinogenesis, a TIPE2 plasmid was introduced into gastric cell lines and TIPE2 function was examined. Colony-forming assays showed that restoration of TIPE2 expression in gastric cells significantly suppressed cell proliferation. Analysis by flow cytometry showed that the number of cells in the S phase of the cell cycle was reduced concomitant with TIPE2 expression, and cell apoptosis was maintained at a low level. Microarray and western blot analyses revealed that TIPE2 selectively up-regulated N-ras and p27 expression. The role of p27 in mediating TIPE2-associated cell growth inhibition was verified by a p27 siRNA interference assay. In this study, we proved that TIPE2 is an inhibitor of gastric cancer cell growth, and suggest that TIPE2 might promote a p27-associated signaling cascade that leads to restored control of the cell cycle and cell division. Our results provide a new molecular mechanism by which TIPE2 may regulate proliferation of gastric cells.

BackgroundThe association between low‐density lipoprotein cholesterol, high‐density lipoprotein cholesterol, and triglycerides with cardiovascular disease (CVD) has been well studied. No previous studies considered trajectory of these lipids jointly. This study aims to characterize longitudinal trajectories of lipid profile jointly and examine its impact on incident CVD.Methods and ResultsA total of 9726 participants (6102 men), aged from 20 to 58 years who had lipids repeatedly measured 3 to 9 times, were included in the study. Three distinct trajectories were identified using the multivariate latent class growth mixture model: inverse U‐shape (18.72%; n=1821), progressing (66.03%; n=6422), and U‐shape (15.25%; n=1483). Compared with the U‐shape class, the adjusted hazard ratio and 95% CI were 1.33 (1.05–1.68) and 1.49 (1.14–1.95) for the progressing and inverse U‐shape class, respectively. The area under the curve was calculated using the integral of the model parameters. In the adjusted model, total and incremental area under the curve of lipid profile were significantly associated with CVD risk. Furthermore, the model‐estimated levels and linear slopes of lipids were calculated at each age point according to the latent class growth mixture model model parameters and their first derivatives, respectively. After adjusting for covariates, standardized odds ratio of slope increases gradually from 1.11 (1.02, 1.21) to 1.21 (1.12, 1.31) at 20 to 40 years and then decreased to 1.02 (0.94, 1.11) until 60 years.ConclusionsThese results indicate that the lipids profile trajectory has a significant impact on CVD risk. Age between 20 and 42 years is a crucial period for incident CVD, which has implications for early lipids intervention.

BackgroundPyruvate kinase isozymes M2 (PKM2), as a member of pyruvate kinase family, plays a role of glycolytic enzyme in glucose metabolism. It also functions as protein kinase in cell proliferation, signaling, immunity, and gene transcription. In this study, the role of PKM2 in neuropathic pain induced by chronic constriction injury (CCI) was investigated.MethodsRats were randomly grouped to establish CCI models. PKM2, extracellular regulated protein kinases (EKR), p-ERK, signal transducers and activators of transcription (STAT3), p-STAT3, phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) and p-PI3K/AKT proteins expression in spinal cord was examined by Western blot analysis. Cellular location of PKM2 was examined by immunofluorescence. Knockdown of PKM2 was achieved by intrathecal injection of specific small interfering RNA (siRNA). Von Frey filaments and radiant heat tests were performed to determine mechanical allodynia and thermal hyperalgesia respectively. Lactate and adenosine triphosphate (ATP) contents were measured by specific kits. Tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) levels were detected by ELISA kits.ResultsCCI markedly increased PKM2 level in rat spinal cord. Double immunofluorescent staining showed that PKM2 co-localized with neuron, astrocyte, and microglia. Intrathecal injection of PKM2 siRNA not only attenuated CCI-induced ERK and STAT3 activation, but also attenuated mechanical allodynia and thermal hyperalgesia induced by CCI. However, PKM2 siRNA failed to inhibit the activation of AKT. In addition, PKM2 siRNA significantly suppressed the production of lactate and pro-inflammatory mediators.ConclusionOur findings demonstrate that inhibiting PKM2 expression effectively attenuates CCI-induced neuropathic pain and inflammatory responses in rats, possibly through regulating ERK and STAT3 signaling pathway.