Comparative proteomic analysis of different stages of breast cancer tissues using ultra high performance liquid chromatography tandem mass spectrometer.

BACKGROUND: Breast cancer is the fifth most prevalent cause of death among women worldwide. It is also one of the most common types of cancer among Malaysian women. This study aimed to characterize and differentiate the proteomics profiles of different stages of breast cancer and its matched adjacent normal tissues in Malaysian breast cancer patients. Also, this study aimed to construct a pertinent protein pathway involved in each stage of cancer. METHODS: In total, 80 samples of tumor and matched adjacent normal tissues were collected from breast cancer patients at Seberang Jaya Hospital (SJH) and Kepala Batas Hospital (KBH), both in Penang, Malaysia. The protein expression profiles of breast cancer and normal tissues were mapped by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The Gel-Eluted Liquid Fractionation Entrapment Electrophoresis (GELFREE) Technology System was used for the separation and fractionation of extracted proteins, which also were analyzed to maximize protein detection. The protein fractions were then analyzed by tandem mass spectrometry (LC-MS/MS) analysis using LC/MS LTQ-Orbitrap Fusion and Elite. This study identified the proteins contained within the tissue samples using de novo sequencing and database matching via PEAKS software. We performed two different pathway analyses, DAVID and STRING, in the sets of proteins from stage 2 and stage 3 breast cancer samples. The lists of molecules were generated by the REACTOME-FI plugin, part of the CYTOSCAPE tool, and linker nodes were added in order to generate a connected network. Then, pathway enrichment was obtained, and a graphical model was created to depict the participation of the input proteins as well as the linker nodes. RESULTS: This study identified 12 proteins that were detected in stage 2 tumor tissues, and 17 proteins that were detected in stage 3 tumor tissues, related to their normal counterparts. It also identified some proteins that were present in stage 2 but not stage 3 and vice versa. Based on these results, this study clarified unique proteins pathways involved in carcinogenesis within stage 2 and stage 3 breast cancers. CONCLUSIONS: This study provided some useful insights about the proteins associated with breast cancer carcinogenesis and could establish an important foundation for future cancer-related discoveries using differential proteomics profiling. Beyond protein identification, this study considered the interaction, function, network, signaling pathway, and protein pathway involved in each profile. These results suggest that knowledge of protein expression, especially in stage 2 and stage 3 breast cancer, can provide important clues that may enable the discovery of novel biomarkers in carcinogenesis.

The BRCA1 and BRCA2 Genes in Early-Onset Breast Cancer Patients.

Approximately 5-10% of breast cancers are attributable to genetic susceptibility. Mutations in the BRCA1 and BRCA2 genes are the best known genetic factors to date. The goal of this study was to determine the structure and distribution of haplotypes of the BRCA1 and BRCA2 genes in early-onset breast cancer patients. We enrolled 70 patients diagnosed with early-onset breast cancer. A total of 21 SNPs (11 on BRCA1 and 10 on BRCA2) and 1 dinucleotide deletion on BRCA1 were genotyped using nested allele-specific PCR methods. Linkage disequilibrium (LD) analysis was conducted, and haplotypes were deduced from the genotype data. Two tightly linked LD blocks were observed on each of the BRCA1 and BRCA2 genes. Variant-free haplotypes (TAT-AG for BRCA1 and ATA-AAT for BRCA2) were observed at a frequency of more than 50% on each gene along with variable frequencies of derived haplotypes. The variant 3'-subhaplotype CGC displayed strong LD with 5'-subhaplotypes GA, AA, and GG on BRCA1 gene. Haplotypes ATA-AGT, ATC-AAT, and ATA-AAC were the variant haplotypes frequent on BRCA2 gene. Although the clinical significance of these derived haplotypes has not yet been established, it is expected that some of these haplotypes, especially the less frequent subhaplotypes, eventually will be shown to be indicative of a predisposition to early-onset breast cancer.

Myxoid liposarcoma of the breast in a 25-year-old female as a diagnostic pitfall in fine needle aspiration cytology: report of a rare case.

Primary sarcomas of the breast are extremely rare comprising less than 1.0% of all malignant tumors of the breast. It is even rarer to be reported in a 25-year-old female. This can cause a diagnostic dilemma not only for the clinician but also for the cytopathologist. A 25-year-old woman presented with a well defined firm, mobile lump in her right breast. With fine needle aspiration cytology (FNAC) and ultrasonography a diagnosis of fibroadenoma was made. The patient underwent lumpectomy. Histopathologically it was diagnosed as myxoid liposarcoma. This case is reported to highlight the fact that, even though rare in young females but the possibility of a breast lump being a myxoid liposarcoma does exist. This report discusses a primary myxoid liposarcoma of female breast, considers cytologic differential diagnoses with review of the relevant literature.