Identification of Serum Biomarkers for Biliary Tract Cancers by a Proteomic Approach Based on Time-of-Flight Mass Spectrometry.

Biliary tract cancers (BTCs) are lethal malignancies currently lacking satisfactory methods for early detection and accurate diagnosis. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) is a promising diagnostic tool for this disease. In this pilot study, sera samples from 50 BTCs and 30 cholelithiasis patients as well as 30 healthy subjects from a population-based case-control study were randomly grouped into training set (30 BTCs, 20 cholelithiasis and 20 controls), duplicate of training set, and blind set (20 BTCs, 10 cholelithiasis and 10 controls); all sets were analyzed on Immobilized Metal Affinity Capture ProteinChips via SELDI-TOF-MS. A decision tree classifier was built using the training set and applied to all test sets. The classification tree constructed with the 3,400, 4,502, 5,680, 7,598, and 11,242 mass-to-charge ratio (m/z) protein peaks had a sensitivity of 96.7% and a specificity of 85.0% when comparing BTCs with non-cancers. When applied to the duplicate set, sensitivity was 66.7% and specificity was 70.0%, while in the blind set, sensitivity was 95.0% and specificity was 75.0%. Positive predictive values of the training, duplicate, and blind sets were 82.9%, 62.5% and 79.2%, respectively. The agreement of the training and duplicate sets was 71.4% (Kappa = 0.43, u = 3.98, P < 0.01). The coefficient of variations based on 10 replicates of one sample for the five differential peaks were 15.8-68.8% for intensity and 0-0.05% for m/z. These pilot results suggest that serum protein profiling by SELDI-TOF-MS may be a promising approach for identifying BTCs but low assay reproducibility may limit its application in clinical practice.

[Serum proteomic spectra of esophageal squamous cell carcinoma patients analyzed with IMAC3 protein chip].

BACKGROUND & OBJECTIVE: Serum protein fingerprinting technology can help to identify the molecular changes related to esophageal carcinogenesis. This study was to screen serum markers and establish the predictive models that may be of help to serologic diagnosis of esophageal squamous cell carcinoma (ESCC). METHODS: Serum samples were collected from 68 ESCC patients and 44 age-and sex-matched healthy subjects, and randomized into a training set (55 ESCC patients and 35 healthy subjects) and a blind testing set (13 ESCC patients and 9 healthy subjects). Serum samples were applied to immobilized metal affinity capture (IMAC3) proteinchip surfaces and tested by surface-enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF-MS). The data were analyzed by Biomarker Wizard software to screen serum proteomic biomarkers. Decision classification tree models were established by bioinformatics. Double-blind test was used to determine the sensitivity and specificity of the classification tree models. RESULTS: A total of 78 effective protein peaks were detected at the molecular range of 1.5 to 20 ku, among which 25 were significantly different between ESCC patients and healthy subjects (P<0.001). All the peptide pattern data were sampled randomly for 1,000 times using 3-cross validation approach, and 1,000 decision tree models were obtained. Twenty decision trees with the highest cross validation rate were chosen to construct the classification models which can differentiate ESCC patients from healthy subjects. With these decision trees, 18 samples were correctly forecasted from 22 blind testing samples, with a sensitivity of 92.31% and a specificity of 66.67%. CONCLUSION: SELDI-TOF-MS technique combined with decision tree model can help to identify serum proteomic biomarkers related to ESCC and the predictive models can discriminate ESCC patients from healthy people effectively.

Detection of mutant p53 protein in workers occupationally exposed to benzidine.

To investigate the expression of mutant p53 protein in workers occupationally exposed to benzidine, we detected mutant p53 protein by immuno-PCR assay in the serum of 331 benzidine-exposed healthy workers, while we classified exfoliated urothelial cells in urine samples with Papanicoloau's grading (PG). The Papanicoloau's grading classified exfoliated urothelial cells of the subjects from grade I (normal cells) to grade III (suspicious malignant cells). The subjects were also divided into high, medium and low exposure groups according to the exposure intensity index. The results revealed that mutant p53 protein in the medium and high exposure groups were significantly higher than the in low exposure group (p<0.05), and in PG II and III were significantly higher than in the PG I (p<0.05). There was no significant differences among Papanicoloau's gradings strata in the low exposure group on the incidence and quantity of mutant p53 protein. In the medium and high exposure groups, the incidence and/or quantity of mutant p53 protein in the stratum of PG II and/or III were significantly higher than that of PG I (p<0.05). Detection of mutant p53 protein in conjunction with benzidine exposure level and Papanicoloau's gradings of exfoliated urothelial cells could provide more information to help us elevate surveillance efficiency and diagnose bladder cancer in the early period.

[Studies of genetic polymorphisms of ADH2 and ALDH2 among the Han population in Luoyang China].

In order to investigate genetic polymorphisms of ADH2 and ALDH2 among the Han population in Luoyang City,portions of exon 3 of ADH2 and exon 12 of ALDH gene were amplified by using polymerase chain reaction. The amplified products were electrophoresed on 10% undenatured vertical polyacrylamide gels and stained with argentine. Frequencies of ADH2*1 and ADH2*2 alleles are 42.86% and 57.14%. Frequencies of three genotypes of ADH2 are 22.86%,40.00% and 37.14%,respectively. Frequencies of ALDH2*1 and ALDH2*2 alleles are 85.24% and 14.76%. Genotype frequencies of ALDH2 loci are 71.43%,27.62% and 0.95%,respectively. Genetic polymorphisms of ADH2 and ALDH2 among the Han population in Luoyang City are different from those among Taiwanese and Shanghainese. Frequency of ALDH2*1/*1 in Luoyang people is higher than those in Shanghai and Taiwan. Therefore,there is a higher resistance to alcohol drinking in the Han population in Luoyang.