Molecular characteristics of matched brain metastasis (BM) versus the primary breast cancer (PBC)

Abstract #2028

Background: Brain is increasingly a site of relapse in breast cancer patients, however the molecular patho-physiology of this process is not well understood. Using a novel assay allowing high-throughput analysis of gene expression from formalin-fixed paraffin-embedded (FFPET) tumor samples, we compared molecular characteristics of BM with those of the PBC in a series of breast cancer patients who underwent excision of brain metastasis.
 Methods: In each patient we performed molecular analysis of paired archived FFPET specimens from both the PBC and excised BM. Of the 37 pairs of PBC/BM samples, 24 pairs had sufficient pathology material for molecular analysis. Patient characteristics: mean age at PBC diagnosis was 46.7 years (range 27-67 years); 7 (29%) ER+, 17 (71%) ER-, 12 (50%) HER2-positive(3+). We performed cDNA-mediated annealing, selection, extension and ligation (DASL) assay (Illumina Corp) for expression of 502 known cancer genes, using 200 ng RNA. Statistical analysis for microarrays (SAM) accounting for the pairing of the primary and metastasized tumors was used to identify differentially expressed genes while controlling the false discovery rate (FDR <0.01). BeadStudio™ Absolute correlation clustering was used to cluster samples based on their expression profiles.
 Results: In only 7 (29%) cases matched PBC and BM pair clustered together on unsupervised hierarchical clustering, the pairs in remaining cases clustered apart. Comparison of the two groups (PBC and BM) showed that 41 genes were up regulated in BM, including proliferation genes (CDC2, CDC25a, CCNA2 and E2F family), anti-apoptotic (BIRC5), DNA repair (RAD51, -54b, XRCC2, BRCA2, BARD1, TOP1), angiogenesis (VEGF), and development of drug resistance (ABCB1, -G2). In contrast, the 43 genes that were down regulated in BM included those associated with invasion (MMP2, -3, -14), cellular motility, and epithelial to mesenchymal transformation (CDH11). Additional analysis to validate these trends and to identify potential therapeutic targets is underway.
 Conclusions: Although some BM retain remarkable similarity to the PBC, majority exhibit considerable deviation in their gene expression profile. These “adaptive” changes include greater resistance to drug therapy, increased DNA repair, a reversal back to the epithelial phenotype and decreased capacity for cell motility and invasion.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2028.

CHEK2 variants predispose to benign, borderline and low-grade invasive ovarian tumors

OBJECTIVE

Three founder alleles of the CHEK2 gene have been associated with predisposition to a range of cancer types in Poland. Two founder alleles (1100delC and IVS2 + 1G >A) result in a truncated CHEK2 protein and the other is a missense substitution, leading to the replacement of a threonine with an isoleucine (I157T).

METHODS

To establish if these variants play a role in the etiology of ovarian tumors, we genotyped 1108 Polish women with various types of ovarian tumors and 4000 controls for the three CHEK2 variants. We included 539 Polish women with benign ovarian cystadenomas, 122 women with borderline ovarian malignancies and 447 women with invasive ovarian cancer.

RESULTS

Positive associations were seen with the CHEK2 I157T missense variant and ovarian cystadenomas (OR = 1.7; P = 0.005), with borderline ovarian cancers (OR = 2.6; P = 0.002) and with low-grade invasive cancers (OR = 2.1; P = 0.04). There was no association with ovarian cancer of high grade (OR = 1.0). The association between the I157T missense variant was then confirmed in a second sample of Russian patients with borderline ovarian cancers (OR = 2.7; P = 0.06).

CONCLUSION

These data indicate that CHEK2 variants may predispose to a range of ovarian tumor types of low malignant potential, but not to aggressive cancers.

[Alpha fetoproteins in serum of a patients with Hodgkin's disease]

Presence of alfa-fetoprotein was found in serum of patient in whom primary hepatoma was suspected. The post-mortem microscopical examination did not confirm the clinical diagnosis ut showed changes typical for Hodgkin's disease.