Comprehensive molecular biomarker identification in breast cancer brain metastases.

BACKGROUND: Breast cancer brain metastases (BCBM) develop in about 20-30% of breast cancer (BC) patients. BCBM are associated with dismal prognosis not at least due to lack of valuable molecular therapeutic targets. The aim of the study was to identify new molecular biomarkers and targets in BCBM by using complementary state-of-the-art techniques. METHODS: We compared array expression profiles of three BCBM with 16 non-brain metastatic BC and 16 primary brain tumors (prBT) using a false discovery rate (FDR) p < 0.05 and fold change (FC) > 2. Biofunctional analysis was conducted on the differentially expressed probe sets. High-density arrays were employed to detect copy number variations (CNVs) and whole exome sequencing (WES) with paired-end reads of 150 bp was utilized to detect gene mutations in the three BCBM. RESULTS: The top 370 probe sets that were differentially expressed between BCBM and both BC and prBT were in the majority comparably overexpressed in BCBM and included, e.g. the coding genes BCL3, BNIP3, BNIP3P1, BRIP1, CASP14, CDC25A, DMBT1, IDH2, E2F1, MYCN, RAD51, RAD54L, and VDR. A number of small nucleolar RNAs (snoRNAs) were comparably overexpressed in BCBM and included SNORA1, SNORA2A, SNORA9, SNORA10, SNORA22, SNORA24, SNORA30, SNORA37, SNORA38, SNORA52, SNORA71A, SNORA71B, SNORA71C, SNORD13P2, SNORD15A, SNORD34, SNORD35A, SNORD41, SNORD53, and SCARNA22. The top canonical pathway was entitled, role of BRCA1 in DNA damage response. Network analysis revealed key nodes as Akt, ERK1/2, NFkB, and Ras in a predicted activation stage. Downregulated genes in a data set that was shared between BCBM and prBT comprised, e.g. BC cell line invasion markers JUN, MMP3, TFF1, and HAS2. Important cancer genes affected by CNVs included TP53, BRCA1, BRCA2, ERBB2, IDH1, and IDH2. WES detected numerous mutations, some of which affecting BC associated genes as CDH1, HEPACAM, and LOXHD1. CONCLUSIONS: Using complementary molecular genetic techniques, this study identified shared and unshared molecular events in three highly aberrant BCBM emphasizing the challenge to detect new molecular biomarkers and targets with translational implications. Among new findings with the capacity to gain clinical relevance is the detection of overexpressed snoRNAs known to regulate some critical cellular functions as ribosome biogenesis.

Phase II study on the use of intraoperative radiotherapy in early breast cancer.

OBJECTIVE: To report our early experience using the Intrabeam radiotherapy delivery system for intraoperative radiotherapy (IORT) in early breast cancer. METHODS: This is a prospective phase 2 study carried out at the Department of Surgery and Radiology, King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia from December 2010 to November 2012. Females eligible for breast-conserving surgery with biopsy-proven invasive duct carcinoma, and with a mass of 3 cm, with lymphovascular invasion, multifocal lesion, extensive intraductal carcinoma, and positive nodes. Early and late toxicity were recorded using the Radiation Therapy Oncology Group (RTOG) criteria. RESULTS: Forty-five patients were included with a median age of 54 (range: 27-79 years). Thirty-six cases (80%) had tumor <3 cm in diameter, and 36 (67%) have pathologically negative axillary lymph node metastases. None of the patients developed delayed wound healing, postoperative infection requiring intravenous antibiotic, or breast seroma requiring aspiration. Sixteen (36%) received EBRT after IORT. Twelve patients developed radiologically proved fat necrosis. CONCLUSION: The IORT for early stage breast cancer patients using the Intrabeam delivery system was easily implemented in our center with an acceptable toxicity profile and cosmetic outcome.