[Treatment of oligoprogression to immunotherapy resistance in advanced non-small cell lung cancer].

In recent years, the incidence of lung cancer has been increasing year by year. Traditional treatments have limited clinical effects in advanced, driver-gene-negative non-small cell lung cancer. Immune checkpoint inhibitors (ICI) have dramatically changed the treatment landscape of advanced non-small cell lung cancer. However, most patients are suffered from primary and acquired resistance inevitably. Oligoprogression is one of the main progression patterns of acquired resistance. Therefore, it is essential to further understand treatment of oligoprogression to immunotherapy resistance. This article aimed to conduct a systematic review of the treatment of oligoprogression to immunotherapy resistance.

[Status and related factors on the drinking behavior among primary and secondary students in China rural middle and western regions in 2019].

Objective: To analyze the daily drinking behavior and related factors of primary and middle school students in the Nutrition Improvement Program for Rural Compulsory Education Students (NIPRCES) pilot regions. Methods: Multi-stage stratified random cluster sampling method was used to select one to three national pilot counties in 22 provinces in central and western China where the NIPRCES was implemented in 2019. According to different feeding patterns, two primary schools and two middle schools were selected as key monitoring schools. One or two classes were selected from grade 3 to grade 9. The student questionnaire was used to collect the basic information and daily drinking behavior. Taking whether the drinking water ≥5 cups every day as the dependent variable, multivariate logistic regression model was used to analyze the related factors of drinking behavior among students. Results: A total of 27 374 students were included. On average, primary and middle school students in the regions where NIPRCES was implemented had 3.9 cups of water every day. Logistic regression model showed that boys (OR=1.230, P<0.001), primary school students (OR=1.379, P<0.001), father worked outside the home (OR=1.169, P<0.001), both parents worked outside the home (OR=1.228, P<0.001), non-resident students (OR=1.142, P<0.001), the school in the village (OR=1.638, P<0.001) or township (OR=1.358, P<0.001), school feeding (OR=1.252, P<0.001), the school building with flush toilets (OR=1.384, P<0.001) and the central regions (OR=1.300, P<0.001) students were more likely to drink ≥5 cups water every day. Conclusion: The water consumption of primary and middle school students in the pilot regions of NIPRCES is low, and their drinking behaviors are affected by many factors.

[Growth retardation of children and its influencing factors in the Nutrition Improvement Program for Rural Compulsory Education Students in 2019].

Objective: To understand the growth retardation among primary and secondary school students in areas covered by the Nutrition Improvement Program for Rural Compulsory Education Students and its influencing factors to provide evidence for improving the nutrition status of rural students in China. Methods: The multi-stage cluster random sampling method selected 1 550 969 primary and secondary school students aged 6-15 years from China's central and western regions. The ratio of male and female students was balanced. The height was measured, and the growth retardation of students was determined according to the Screening Criteria for School-age Children and Adolescents malnutrition (WS/T 456-2014), from the school and county questionnaire survey related factors. The number of cases and percentages described the growth retardation of students, and the χ2 test was used for comparison between groups. Binary logistic regression was used to analyze students' growth retardation factors. Results: In 2019, the growth retardation rate of primary and secondary school students in areas covered by the Nutrition Improvement Program for Rural Compulsory Education Students was 5.7% (88 631/1 550 969), the growth retardation rate in the western part (7.1%, 66 167/927 954) was higher than that in the central part (3.7%,19 511/533 973) with difference statistically significant (P<0.001). The growth retardation rate of the boys (6.3%,50 665/803 851) were higher than that of girls (5.1%, 37 966/747 118), the difference was statistically significant (P<0.001). The growth retardation rate of primary school students in central China was 3.9%(14 914/380 598), higher than that of junior middle school students (3.0%,4 597/153 375, P<0.001). In contrast, the growth retardation rate of the western junior high school students (7.2%, 21 494/297 217) were higher than that of elementary school students (7.1%, 44 673/630 737), with a difference statistically significant (all P=0.009). Multi-factor logistic regression results showed that, in high income area (OR=0.829, 95%CI: 0.816-0.842, P<0.001), parents providing part of the meal cost (OR=0.948, 95%CI: 0.931-0.965, P<0.001), enterprises providing meals (OR=0.845, 95%CI: 0.805-0.887, P<0.001), schools providing milk (OR=0.780, 95%CI: 0.767-0.793, P<0.001), health education courses (OR=0.702, 95%CI: 0.682-0.723, P<0.001) and other local nutrition improvement efforts (OR=0.739, 95%CI: 0.720-0.758, P<0.001) were negatively correlated with the occurrence of growth retardation, The growth retardation rate of the students was lower. Conclusions: There appeared significant regional, gender, and age differences in the growth retardation rate of primary and middle school students in areas covered by the Nutrition Improvement Program for Rural Compulsory Education Students. Appropriate food supply in schools, health education courses, and parental participation in nutritional improvement was related to children's lower growth retardation rate.

[Anemia prevalence and its influencing factors among students involved in the Nutrition Improvement Program for Rural Compulsory Education Students in 2019].

Objective: To analyze anemia prevalence and its influencing factors of students involved in the Nutritional Improvement Program for Rural Compulsory Education Students in 2019. Methods: From the 2019 surveillance system of the Nutrition Improvement Program for Rural Compulsory Education Students, 47 297 primary and middle school students aged 6-17 were included in the study. Hemoglobin level was tested according to the criteria of WHO 2011. Anemia prevalence of different genders, ages, and regions was analyzed. Results: The average hemoglobin level was 135.19 g/L, with the prevalence of anemia as 8.7% in the children aged 6-17. The prevalence of anemia was 10.0% in girls, higher than that in boys (7.4%). The prevalence rates in western and central areas were 9.8% and 7.1%, respectively. From northwest, southwest, central and south, east, north to northeast areas of China, the anemia rate appeared gradually decreasing (10.2%, 9.7%, 8.3%, 7.5%, 5.7% and 3.5%). The anemia prevalence rates were 8.0%, 8.3%, and 10.9% in children from the 6-, 11-, and 14-17 years age groups, respectively. Logistic regression models revealed that students from schools not using catering software (OR=1.482, 95%CI:1.296-1.694,P<0.001), schools not serving lunch (OR=1.241, 95%CI:1.103-1.395,P<0.001), and from relatively low-income families (OR=1.297, 95%CI:1.211-1.389, P<0.001) showed as risk factors for anemia. After supplementing students' dietary factors, the results showed that students who ate meat three or more times a week had a lower risk of anemia (OR=0.907, 95%CI:0.832-0.989, P=0.026). Conclusions: The Nutritional Improvement Program for Rural Compulsory Education Students had an essential impact on improving the anemia prevalence of primary and middle school students. Family income, school location, economic factors, school feeding, and students' diet programs all impacted the prevalence of anemia.

[Status and influencing factors on the leftover school meals among students the Nutrition Improvement Program for Rural Compulsory Education Students in 2019].

Objective: To analyze the situation and influencing factors of school meals leftover among primary and secondary school students in the area of the Nutrition Improvement Program for Rural Compulsory Education Students, improve the quality of school meals, develop healthy dietary behavior, and reduce food waste. Methods: In 2019, among the 50 monitoring counties that implemented the Compulsory Education Student Nutrition Improvement Program, two primary schools and two junior schools were randomly selected according to different food supply patterns.This study randomly selected one or two classes from grade 3 to grade 9. Basic information and school meals of 26 778 students were collected by using a student questionnaire. Multivariate logistic regression was used to analyze the influencing factors of leftovers rate. Results: 54.93% (14 709) of students wasted school meals, in which the highest rate was the staple food, with the main reason as "not in favor". 11.87% (1 743) of the students wasted school meals 6-7 days a week, with 54.20% (7 957) of students wasted but in less amount. The leftover rate of staple food was the highest (29.78%), followed by vegetables and meat. The main reason of leftovers was that they didn't like this kind of food (33.52%). The rate of school meal waste was higher for girls (OR=1.19,95%CI:1.13-1.25), junior high school students (OR=1.17, 95%CI: 1.11-1.25), resident students (OR=1.06, 95%CI: 1.00-1.12), lower economic level (OR=1.06, 95%CI: 1.00-1.12), parents working outside their houses (OR=1.22, 95%CI: 1.13-1.30), health education classes (OR=1.70, 95%CI: 1.40-2.06), company-based meals (OR=1.89, 95%CI: 1.71-2.07) and school meals were not as good as home food(OR=1.89, 95%CI: 1.78-2.00)(P<0.05). Conclusions: It is common for poor rural primary and middle school students in central and western China to waste school meals, and the reasons were affected by many factors. Reducing food waste requires the joint efforts of individuals, families, schools and society.

[Clinicopathological features of notochordal tumors: a study of 48 cases].

Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of notochordal tumors. Methods: The clinical, radiologic and pathologic data of 48 notochordal tumors were collected from 2008 to 2019 at Shanghai Jiaotong University Sixth People's Hospital. Expression of cytokertin, S-100 protein, vimentin, brachyury and INI1 was detected by immunohistochemistry. The pathologic differential diagnoses and biologic behavior of various types of notochordal tumors were analyzed using the new standard in the 5th edition of WHO tumor classification. Results: Four cases of benign notochordal cell tumor were confined to vertebral body. Histopathologically, they lacked lobular architecture and extracellular myxoid matrix. The tumor cells were vacuolated and had centrally or peripherally located round to oval nuclei, with small nucleoli, without atypia, mimicking mature adipocytes. No mitotic figures were seen. Two cases of poorly differentiated chordoma, from patients aged 12 years and 21 years respectively, were located in cervical vertebra, and were composed of cohesive sheets or nests of epithelioid cells, with focal rhabdoid morphology. There was relatively abundant eosinophilic cytoplasm and scattered cytoplasmic vacuoles. The moderately pleomorphic nuclei were round to ovoid with vesicular chromatin and mitotic figures could be seen. Extracellular myxoid stroma was observed focally. Forty cases of conventional chordoma and two cases of extra-axis chordoma had similar histologic features. All 48 cases expressed cytokeretin, 45 cases expressed brachyury, and two poorly differentiated tumors showed loss of INI1/SMARCB1. Conclusions: There are four subtypes of chordomas: conventional, dedifferentiated, poorly differentiated and extra-axis. Chondroid chordoma is no longer thought to be a distinct entity. Each type has its unique clinicopathological characteristics. Brachyury is highly specific and sensitive for the diagnosis of various notochordal tumors. Poorly differentiated chordoma shows distinct clinicopathological features, including young age and loss of immunohistochemical expression of INI1/SMARCB1, and its diagnosis requires the combined detection of brachyury and INI1/SMARCB1.

[The study of the value of H3F3A G34W immunohistochemical staining in the diagnosis of giant cell tumor of bone].

Objective: To investigate the diagnostic role of H3F3A G34W immunohistochemistry in giant cell tumor of bone. Methods: A total of 275 tumors were collected from 2016 to 2018 at Shanghai Jiaotong University Affiliated Sixth People's Hospital, including 136 giant cell tumors of bone, 31 general osteosarcomas, 3 osteoclast-rich osteosarcomas, 3 brown tumors, 34 chondroblastomas, 29 giant cell tumors of tendon sheath, 20 primary arteromatoid bone cysts and 19 non-ossifying fibromas. Results: Among the 136 cases of giant cell tumor of bone,82 patients were male and 54 were female. The age ranged from 15 to 72 years (median age 38 years). Nuclear positivity for H3F3A G34W was seen in 119/136(87.5%) giant cell tumors of bone and 1/31(3.2%) general osteosarcoma,while all osteoclast-rich osteosarcomas, brown tumors, chondroblastomas, giant cell tumors of tendon sheath, primary arteromatoid bone cysts and non-ossifying fibroma were negative. Conclusions: The monoclonal antibody against the G34W mutated site of H3F3A is a specific biomarker for giant cell tumor of bone and useful for the diagnosis and differential diagnosis of giant cell tumor of bone. Meanwhile,for those cases in which giant cell tumor of bone are diagnosed basing on clinical,pathologic and radiographic features but are negative for H3F3A G34W,should be tested for rare mutations or H3F3A wild type.

Decreasing cytokeratin 17 expression in head and neck cancer predicts nodal metastasis and poor prognosis: The first evidence.

OBJECTIVES: Cytokeratins (CKs) are mainly expressed in epithelial carcinomas and are valuable for making diagnoses and identifying metastatic status. Changes in the expression of individual CKs in certain carcinoma may be relevant to establishing a prognosis. However, the prognostic significance of CKs in head and neck squamous cell carcinoma (HNSCC) remains elusive. Herein, we investigated the diverse and unique expression patterns of Cytokeratin 13 (CK13) and Cytokeratin 17 (CK17) and assessed the role of CK17 as a predictor for HNSCC metastasis and prognosis. METHODS: CK13 and CK17 expressions were evaluated using immunohistochemical tissue microarray (TMA) analysis with 106 patients of HNSCC. To clarify the characterisation of CK17 expression with respect to its ability in predicting metastatic disease, an in vitro study of cells migration/invasion assays was conducted. Furthermore, the correlation of CK17 expression to clinicopathologic variables and prognosis was analyzed using a serial statistical method. RESULTS: CK13 was predominately expressed in non-cancerous tissues and was lost in HNSCC. Decreasing expression of CK17 correlated with cancerous cell migration and invasion (P < .0001) in an in vitro study. CK17 expression was lower in the N1 and N2 nodal metastases category compared to the N0 stage. Moreover, Kaplan-Meier survival analyses showed that a lower CK17 expression was associated with a poorer survival connotation in HNSCC patients (P < .05) with 10-year follow-up. CONCLUSION: Our findings provide the first evidence that CK17 under-expression might be a potential predictor of nodal metastasis and adverse prognosis.

[Role of sleep apnea monitoring management platform in the treatment of patients with obstructive sleep apnea hypopnea syndrome].

Objective:To investigate the clinical significance and value of the sleep apnea monitoring management platform in the treatment of patients with obstructive sleep apnea hypopnea syndrome (OSAHS) by comparing with the traditional continuous positive airway pressure (CPAP) card reader mode.Method:A total of 48 severe adult OSAHS patients from Department of Otorhinolaryngology Head and Neck Surgery-Sleep Medical Center of the Third People's Hospital of Honghe during the period of Nov. 2015 to Aug. 2016 were collected in this prospective study. All of them were diagnosed by PSG and treated with nasal continuous positive airway pressure. They were randomly divided into group A (n=24) and group B (n=24). Group A and B were treated with the traditional CPAP card reader mode and the sleep apnea monitoring management platform respectively. During the follow-up, the compliance, mean blood oxygen saturation, titration pressure, Epworth sleepiness scale after 1, 3, 6 and 12 month treatment were compared between two groups. Ttest was used to analyze the difference. Statistical significance was set at P <0.05.Result:Statistical analysis showed that there were significant difference in the compliance of using CPAP, mean blood oxygen saturation and Epworth sleepiness scale score between the two groups (P < 0.05), but the titration pressure had no difference between the two groups (P>0.05).Conclusion:Compared the sleep apnea monitoring management platform with traditional CPAP card reader mode in the treatment of OSAHS patients, the former could solve the problems during the CPAP use in time, improve the compliance of using CPAP, and which could increase the efficacy of CPAP. Thus, the sleep apnea monitoring management platform is of more clinical value and deserve promotion.

[Repairmen of the rabbit's oral mucosa by tissue engineering technology].

Objective:This experiment proposed to complicate BMMSCs and PLLA/SF scaffolds, to study its repairing ability for rabbit oral mucosa wound, and try to evaluate the most potential mixed proportion of PLLA and SF for tissue engineering. Method:Separating,cultivating and identifying BMMSCs. Observing cell phenotype of BMMSCs after cultivating BMMSCs in P70S30 PLLA/SF scaffold for one week.Observing the structure change of BMMSCs and P70S30PLLA/SF scaffold complexes after oral mucosa transplantation experiment for a week；Comparing the wound healing rate of composite of BMMSCs and PLLA/SF scafold，PLLA/SF scaffold and nature repair. Result:①There wasn't a significant effect of PLLA/SF scaffold on cell phenotype of BMMSCs.②The wounds fused well with the oral mucosa transplanted composite of BMMSCs and P70S30 PLLA/SF scaffold after a week.③The healing rate of composite of BMMSCs and P70S30 scaffold was the highest.The average healing rate of composite of BMMSCs and P70S30 scaffold was 94.8%,whose difference was statistically significant compared with natural healing and pure scaffold(P<0.01). Conclusion:①The complex composed of BMMSCs and PLLA/SF scaffolds has the potential as an ideal scaffold for tissue engineering oral mucosa.②The complex composed of BMMSCs and P70S30 PLLA/SF scaffolds is the most beneficial to wound healing of oral mucosa,and has the greatest potential for constructing tissue engineering oral mucosa.

Elevated plasma levels and monocyte-associated expression of CD137 ligand in patients with acute atherothrombotic stroke.

BACKGROUND: CD137 ligand (CD137L) is expressed by various immune cells and exists in membrane-bound and soluble forms. Recently, CD137L was found to be localized to macrophages in human atherosclerotic lesions and CD137L levels were much higher in atherosclerotic lesions than in normal arteries. However, the role of CD137L with different forms in atherothrombotic stroke remains unclear. PATIENTS AND METHODS: The soluble CD137L (sCD137L) protein and CD137L expression on monocytes were analyzed by an enzyme-linked immunosorbent assay and flow cytometry in peripheral blood of patients with acute ischemic atherosclerotic stroke, atherosclerosis controls and normal controls. RESULTS: During the initial 24h after onset, the stroke patients had elevated plasma sCD137L levels (133.2 pg/ml) and CD137L expression on monocytes [7.9 ± 4.1%, 7.0 ± 4.0 mean fluorescence intensity (MFI)] as compared with normal controls (75 pg/ml, p < 0.05; 4.6 ± 2.4%, 4.1 ± 2.7 MFI, p < 0.05). CONCLUSIONS: The dysregulation of CD137L expression may reflect a persistent chronic inflammatory response that may have been induced during early stages of the disease. Our results strongly suggest that the abnormal expression of CD137L on monocytes may lead to dyregulated CD137L/CD137 signaling and consequently form part of a positive-feedback, inflammation-promoting circuit in stroke, while the elevated sCD137L protein levels may function as a self-regulatory mechanism of CD137/CD137L interaction and costimulation.

Improvement of hyperphagia by activation of cerebral I(1)-imidazoline receptors in streptozotocin-induced diabetic mice.

Imidazoline I1-receptors (I1R) are known to regulate blood pressure and rilmenidine, an agonist, is widely used as antihypertensive agent in clinic. However, the role of I1R in feeding behavior is still unclear. In the present study, we used the agonist of I1R to investigate the effect on hyperphagia in streptozotocin (STZ)-induced diabetic mice. Rilmenidine decreased the food intake of STZ-diabetic mice in a dose-dependent manner. The reduction of food intake was abolished by pretreatment with efaroxan at the dose sufficient to block I1R. Intracerebroventricular (icv) administration of rilmenidine into STZ-diabetic mice also significantly reduced hyperphagia, which was reversed by icv administration of efaroxan. In addition, similar results were observed in STZ-diabetic mice, which received chronic treatment with rilmenidine 3 times daily (t.i.d.) for 7 days. Moreover, the hypothalamic neuropeptide Y (NPY) level was reduced by rilmenidine that was also reversed by pretreatment with efaroxan. In conclusion, the obtained results suggest that rilmenidine can decrease food intake in STZ-diabetic mice through an activation of I1R to lower hypothalamic NPY level.

Stimulatory effect of allantoin on imidazoline I1 receptors in animal and cell line.

Allantoin is known as the agonist of imidazoline receptor, especially the I2 subtype. Effect of allantoin on imidazoline I1 receptor (I1R) relating to reduction of blood pressure and its merit in steatosis are still obscure. Also, farnesoid X receptor (FXR) plays an important role in lipid homeostasis related to I1R activation. Thus, we administered allantoin into high fat diet (HFD)-fed mice showing hypertriglyceridemia and hypercholesterolemia. Allantoin significantly improved hyperlipidemia in HFD mice after 4 weeks of administration. Pretreatment with efaroxan, at a dose sufficient to inhibit I1R activation, attenuated the action of allantoin. In addition, in cultured HepG2 cells, allantoin increased the expression of farnesoid X receptor (FXR). The allantoin-induced FXR expression was blocked by efaroxan. Similar changes were observed in the expressions of FXR-targeted genes. Otherwise, allantoin also lowered systolic blood pressure (SBP) in HFD mice that can be blocked by efaroxan. Taken together, allantoin has an ability to activate I1R for improvement of metabolic disorders.

Opening of ATP-sensitive potassium channel by insulin in the brain-induced insulin secretion in Wistar rats.

Cerebral insulin can regulate glucose homeostasis via activation of the parasympathetic nervous system, which results in the reduction of hepatic glucose output. However, the precise mechanism(s) through which cerebral insulin directly exerts an effect on insulin secretion remains unclear. In the present study, we found that cerebral administration of insulin caused an increase of plasma insulin concentration and a concomitant decrease in plasma glucose levels within one hour. These effects were blocked by vagotomy or intraperitoneal injection of 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide, a specific M (3) antagonist. The mediating influence of parasympathetic activation can thus be considered. The adenosine triphosphate-sensitive potassium (K-ATP) channel is a key mediator of the cerebral action of insulin. The plasma glucose-lowering action of insulin was abolished by cerebral administration of glibenclamide or repaglinide at concentrations sufficient to block K-ATP channels. In conclusion, our findings suggest that cerebral insulin may induce insulin release by stimulating the opening of K-ATP channels, which in turn activate parasympathetic tone in pancreatic tissue.

Determination of particulate-bound formaldehyde from burning incense by solid phase microextraction.

This work studied the feasibility of using a solid phase microextraction (SPME) fiber for sampling and analysis of gaseous formaldehyde as well as particulate-bound formaldehyde from burning Chinese incense. The SPME fiber with PDMS/DVB coating were partially coated with o-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine hydrochloride (PFBHA), and used for sampling formaldehyde. The sampling rate for formaldehyde and its dependence on temperature, relative humidity and sampling time were observed. The same PFBHA treated fibers were, in parallel, exposed to incense burning smoke with pre-filtration and without pre- filtration for 0.5-1 min. The NIOSH method 2541 using an XAD-2 tube at a flow rate of 0.1 Lpm was also applied for sampling simultaneously. The results demonstrate that commercially available PDMS/DVB fibers partially coated with PFBHA are capable of sampling the gas phase of formaldehyde as well as particulate-bound formaldehyde. The determined level of formaldehyde was close to the result obtained by the NIOSH method 2541. However, a reduction of the fiber's formaldehyde loading capacity in the aerosol sampling in comparison with gas sampling was noticed. This indicates that the particulate characteristics, and their bound chemicals other than formaldehyde may influence the maximum loading capacity of formaldehyde, and some characteristic particulates in high concentrations may even deteriorate the fiber coating.

Human mesenchymal tumour-associated macrophages differentiate into osteoclastic bone-resorbing cells.

The cellular mechanisms which account for the formation of osteoclasts and bone resorption associated with enlarging benign and malignant mesenchymal tumours of bone are uncertain. Osteoclasts are marrow-derived, multinucleated, bone-resorbing cells which express a macrophage phenotype. We have determined whether tumour-associated macrophages (TAMs) isolated from benign and malignant mesenchymal tumours are capable of differentiating into osteoclasts. Macrophages were cultured on both coverslips and dentine slices for up to 21 days with UMR 106 osteoblastic cells in the presence of 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) and human macrophage colony-stimulating factor (M-CSF) or, in the absence of UMR 106 cells, with M-CSF and RANK ligand. In all tumours, the formation of osteoclasts from CD14-positive macrophages was shown by the formation of tartrate-resistant-acid-phosphatase and vitronectin-receptor-positive multinucleated cells which were capable of carrying out lacunar resorption. These results indicate that the tumour osteolysis associated with the growth of mesenchymal tumours in bone is likely to be due in part to the differentiation of mononuclear phagocyte osteoclast precursors which are present in the TAM population of these lesions.

AP2 protein expression as a diagnostic marker in soft tissue tumours.

PURPOSE/METHODS: The aP2 gene product (aP2 protein) is known to be expressed by preadipocytes and other immature fat cells in vitro. A mouse monoclonal antibody raised against an 18 amino acid segment of the aP2 protein was found to react with lipoblasts and fetal fat cells in paraffin sections of soft tissue tumours of adipose differentiation. In this immunohistochemical study, we have further examined the diagnostic utility of aP2 expression in distinguishing tumours of adipose differentiation from other benign and malignant soft tissue tumours.Result and discussion aP2 was strongly expressed by lipoblasts in lipoblastomas and all types of liposarcoma as well as brown fat cells in hibernomas. Optimal conditions for immunohistochemical identification of lipoblasts in tumours of adipose differentiation was noted when the antibody was diluted 1:30 to 1:50. Small lipoblast-like fat cells in pleomorphic lipoma and spindle cell lipoma also showed variable staining for aP2 at this dilution of the antibody. Most benign and malignant soft tissue tumours were distinguished by their absence of staining for aP2 protein, but some cases of myxoma, malignant fibrous histiocytoma, synovial sarcoma and leiomyosarcoma contained tumour cells which reacted for aP2. aP2 protein expression is likely to prove a useful means of distinguishing lipoblasts in liposarcoma but it should be used as part of a tumour panel to exclude expression in other forms of mesenchymal tumour.