Angiographically Occult Subarachnoid Hemorrhage: Yield of Repeat Angiography, Influence of Initial CT Bleed Pattern, and Sources of Diagnostic Error in 242 Consecutive Patients

BACKGROUND AND PURPOSE

Nearly 20% of patients with spontaneous SAH have no definitive source on initial DSA. The purpose of this study was to investigate the timing and yield of repeat DSA, to clarify the influence of initial CT bleed pattern, and to characterize sources of diagnostic error in this scenario.

MATERIALS AND METHODS

We evaluated the yield of repeat DSA and clinical outcomes stratified by hemorrhage pattern on CT in consecutive patients with nontraumatic SAH with negative initial DSA findings at a referral center. Cases in which the culprit lesion was subsequently diagnosed were classified as physiologically occult (ie, undetectable) on the initial DSA, despite adequate technique and interpretation or misdiagnosed due to operator-dependent error.

RESULTS

Two hundred forty-two of 1163 (20.8%) patients with spontaneous SAH had negative initial DSA findings between 2009 and 2018. The SAH CT pattern was nonperimesencephalic (41%), perimesencephalic (36%), sulcal (18%), and CT-negative (5%). Repeat DSA in 135/242 patients (55.8%) revealed a source in 10 patients (7.4%): 4 saccular aneurysms, 4 atypical aneurysms, and 2 arteriovenous shunts. The overall yield of repeat DSA was 11.3% with nonperimesencephalic and 2.2% for perimesencephalic patterns. The yield of the second and third DSAs with a nonperimesencephalic pattern was 7.7% and 12%, respectively. Physiologically occult lesions accounted for 6/242 (2.5%) and operator-dependent errors accounted for 7/242 (2.9%) of all angiographically occult lesions on the first DSA.

CONCLUSIONS

Atypical aneurysms and small arteriovenous shunts are important causes of SAH negative on angiography. Improving DSAs technique can modestly reduce the need for repeat DSA; however, a small fraction of SAH sources remain occult despite adequate technique. These findings support the practice of repeating DSA in patients with a nonperimesencephalic SAH pattern.

Increased Expression of Inflammatory Genes in Pregnancy-Associated Breast Cancers

Introduction: Epidemiological studies have shown that women of all ages experience a transient increase in the risk of developing breast cancer following pregnancy. Furthermore, breast cancers detected soon after a completed pregnancy (pregnancy-associated breast cancers, or PABCs) have a worse prognosis than those detected at more distant intervals (Schedin 2006). We previously found evidence for increased expression of inflammatory genes in the human breast following pregnancy. (Asztalos et al. 2008). In this study we analyzed the same gene set in human breast cancer tissue, to investigate the role of inflammation in pregnancy associated breast cancers.Patients and Methods: Women ≤ 45 years of age with breast cancer were eligible for the study, and were categorized as either nulliparous, recently pregnant or distantly pregnant. Thirteen nulliparous, 14 recently pregnant (<2 years since pregnancy) and 15 distantly pregnant (5-10 years) patients were identified. Tumor regions were isolated from formalin-fixed paraffin embedded tissues using Laser Capture Microdissection, followed by RNA extraction and cDNA synthesis. Genes of interest were preamplified linearly, followed by real time PCR. We chose 59 genes involved in the processes of inflammation, ECM remodeling and angiogenesis. A small number of breast cancer prognostic genes were also included. Gene expression between groups was compared using either t-test, ANOVA or unsupervised hierarchical clustering.Results: When recent and distant PABCs were combined and compared to the nulliparous group, we observed a number of significantly differentially regulated genes, such as CXCL1, THBS1, ELN, IL11 and MMP3. Upregulation of CXCL1 in the post-pregnant samples is interesting since CXCL1 is an important inflammatory chemokine, with implications in cancer. THBS1, a natural inhibitor of neovascularization and tumorigenesis, was downregulated in the post-pregnancy group. In this early analysis, we did not observe a difference in gene expression between recent and distant pregnancies, possibly due to the limited number of samples. However, immunoglobulin A showed a trend towards upregulation in the recent pregnancy group, suggesting an enhanced state of immune activity in the cancers occurring in the recently pregnant breast. When concerted gene expression was compared by non-supervised hierarchical clustering, we found that PABCs (both recent and distant) had more frequent associations with inflammation associated gene-expression patterns than those of nulliparous patients.Conclusions: This is the first study to address the hypothesis suggesting the role of post-pregnancy events, such as inflammation, ECM remodeling and angiogenesis in the etiology and aggressiveness of PABCs by looking at a set of human breast cancers with known pregnancy history. We show that the cancers of patients detected post-pregnancy are more frequently associated with an inflammation-associated gene expression pattern, than those of nulliparous women. The exact role of inflammation in the aggressiveness of PABCs remains to be further elucidated.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5158.

T47D/PKCα Cells Are Nonmigratory and Noninvasive In Vitro Despite Tamoxifen Resistance In Vivo

Background: We have previously reported that overexpression of PKCα in T47D (T47D/PKCα) breast cancer cells results in hormone independence, growth inhibition by estradiol, and tamoxifen resistance (Chisamore, 2001). This has clinical relevance because we have shown that PKCα overexpression may predict disease recurrence and tamoxifen treatment failure suggesting consideration of other treatments (Tonetti, 2003). Further characterization reveals that T47D/PKCα cells are noninvasive in vitro compared to T47D/neo control cells in Matrigel invasion assays and that knockdown of PKCα reverses the phenotype (Perez White, AACR 2009). We have further characterized the in vitro phenotype of T47D/PKCα cells using migration assay and profiling of proteins associated with epithelial-mesenchymal transition (EMT). Adherens junctions are made of a complex of proteins including E-cadherin whose dissolution is thought to play a role in EMT. E-cadherin can be transcriptionally repressed by the embryonic transcription factor Snail1. Generally, cells that lose expression of E-cadherin gain expression of N-cadherin and/or vimentin which is correlated to increased migration, invasion, and metastasis.Methods: To determine migration, cells were plated in serum-free media into Boyden chambers for 24 h with media containing 10% fetal bovine serum as chemoattractant. Protein expression levels were determined by western blot of whole cell extracts and transcript levels by RT-qPCR. Statistical analyses were performed by t-test with GraphPad Prism 5.Results: Migration assay results show that T47D/PKCα cells are nonmigratory compared to T47D/neo cells (P < 0.0001). Western blots show that there is significantly lower expression of E-cadherin in T47D/PKCα cells compared to T47D/neo cells (P < 0.005). However, transcripts of E-cadherin are expressed at 3-fold higher levels in T47D/PKCα cells compared to T47D/neo cells. Neither cell line expresses vimentin, N-cadherin, or Snail1 proteins.Conclusions: T47D/PKCα cells have reduced invasive and migratory potential even though they have decreased expression of E-cadherin. Results indicate that regulation of E-cadherin may be due to translational repression or increased degradation due to increased transcripts and absence of a transcriptional repressor. In summary, despite the fact that PKCα overexpression correlates with tamoxifen resistance, these tumors may have a better prognosis due to the less invasive and migratory nature of these cells. Future mechanistic and clinical studies are needed to determine the full prognostic impact of PKCα tumor overexpression in patients.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6173.

Estradiol Induced Regression of T47D:A18/PKCα Tumor Involves Translocation of Estrogen Receptor alpha from the Nucleus to the Cytoplasm

Background: Resistance to tamoxifen (TAM) is one of the most challenging problems in the treatment of breast cancer. In our laboratory we have developed a PKCα overexpressing T47D:A18 cell line which is TAMresistant and 17β estradiol (E2) independent compared to the E2 dependent T47D:A18/neo cell line (Chisamore et al, 2001). PKCα overexpression is known to be associated with TAM treatment failure in breast cancer (Tonetti et al, 2003). This T47D:A18/PKCα model exhibits E2-induced tumor regression in in vivo or when grown in matrigel (3D matrix) but not on 2D plastic. Recently we have demonstrated that tumor regression involves participation of estrogen receptor alpha (ERα), Fas/FasL and the extracellular matrix (Zhang et al, 2009). Interestingly membrane impermeable E2-BSA conjugate mediates growth inhibition of T47D:A18/PKCα colonies in matrigel similar to E2 suggesting a potential role of extranuclear ERα. On the basis of our preliminary data we investigated whether extranuclear ERα may play a critical role in E2-induced tumor regression.Materials and methods: T47D:A18/PKCα cells were injected into mammary fat pads of 20 ovariectomized athymic mice. Mice were left untreated and tumors were allowed to grow until the mean tumor size reached 0.5 cm2, then 10 mice were implanted with a 1.0 cm E2 capsule and the other 10 continued with no treatment (control). T47D:A18/neo tumors were also established in 10 athymic mice in the presence of E2. Four micrometer thick sections were prepared from the paraffin embedded T47D:A18/PKCα tumor tissues of control and E2-treated mice and T47D:A18/neo tumors. For immunofluorescence staining, alexa fluor 488 and Cy3 fluorescence tagged secondary antibodies were used against ERα and β-actin primary antibodies respectively.Results: Immunofluorescence images of T47D:A18/PKCα tumor sections from untreated control mice showed that the ERα was mainly localized in the nucleus. Interestingly, treatment with E2 resulted in significant translocation of ERα from the nucleus to the cytoplasm and the plasma membrane of tumor cells. Immunofluorescence analysis of tumor sections obtained from E2 treated mice indicated that approximately 5-10% of cells contained ERα localized to the plasma membrane whereas the majority of ERα was localized to the cytosol. However in T47D:A18/neo tumors the majority of ERα was found in the nucleus suggesting the involvement of the ERE mediated classical pathway in tumor growth.Discussion: This is the first time we are reporting that E2-induced T47D:A18/PKCα tumor regression is accompanied by translocation of ERα to extranuclear sites. E2-induced tumor regression observed in our pre-clinical model suggests E2 or an E2-like compound may be a potential treatment option for patients harboring PKCα overexpressing tumors. Furthermore the extranuclear ERα signaling pathway may be an attractive therapeutic target to treat PKCα overexpressing tumors that are refractory to current endocrine therapies.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4140.

2-(4-Hydroxyphenyl)-Benzo[b]thiophen-6-ol, an Estrogen-Like Compound, Induces Apoptosis in T47D/PKCα Breast Cancer Cells

Background: Tamoxifen (TAM) treatment failure is a major obstacle encountered in the clinical setting. Our lab has previously shown that constitutive overexpression of PKCα imparts a TAM resistant/ hormone independent phenotype in the T47D:A18 breast cancer cell line. Furthermore 17β-estradiol (E2) inhibits tumor growth in vivo as well as inhibits colony formation when cells are grown in 3D Matrigel (Zhang, 2009). Before TAM treatment was introduced, breast cancer patients received high-dose E2 and diesthystilbesterol (DES) treatment. DES treated patients may have a survival advantage over TAM treated patients in the long term (Peethambaram,1999). Others have shown that E2 can have inhibitory effects on MCF-7 cells both in vitro and in vivo (Lewis-Wambi, 2009). Taken together, this suggests an estrogenic compound may be efficacious for TAM-resistant breast cancer. The present study was designed to evaluate the effect of an estrogenic compound, 2-(4-hydroxyphenyl)-benzo[b]thiophen-6-ol (BTC), related to the SERMs raloxifene and arzoxifene, on the T47D:A18/PKCα breast cancer cell line.Methods: To determine if BTC can activate estrogen regulated genes we preformed an ERE-luciferase reporter assay 24 hours after BTC treatment. 3D Matrigel colony formation assay was performed to determine if BTC could inhibit colony formation. Colonies were stained and counted on day 10. To determine if apoptosis was occurring, cells were grown in Matrigel and the TUNEL Assay was performed on Day 6.Results: T47D:A18/PKCα cells showed a 31-fold induction in ERE-luciferase reporter activity when treated with BTC (10-7M) compared to 7-fold induction when treated with E2. In the T47D:A18/Neo parental cell line, BTC induced a 40-fold induction whereas estradiol induced a 96-fold induction. In the Matrigel colony formation assay T47D:A18/PKCα cells formed significantly fewer colonies when treated with BTC. Conversely, in the T47D:A18/Neo parental cell line BTC enhanced colony formation similar to E2 treatment. Our results indicate that BTC was able to induce significant apoptosis on day 6 (P= 0.038) as determined by the TUNEL Assay. Therefore BTC acts similarly to estradiol by inhibiting T47D:A18/PKCα colony formation and inducing apoptosis when cells are grown in Matrigel.Conclusion: These findings suggest that BTC is a potential lead compound in the treatment of PKCα overexpressing breast cancer. Furthermore, BTC was shown to be a potent inducer of the cytoprotective enzyme NQO1 in the Hepa 1c1c7 cell system as well as a strong activator of antioxidant responsive elements (Yu, 2007) indicating it may have the added benefit of chemoprotective effects which are absent in estradiol treatment. Further understanding of the mechanism in which BTC induces apoptosis in the T47D:A18/PKCα cell line may result in a clinical advantage to estradiol treatment including fewer side effects.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5140.

Preferential maternal derivation in inv dup(15): analysis of eight new cases

Eight patients are reported with a de novo extra inverted duplicated chromosome 15. The abnormal chromosome was considered to be the same in all cases, but its precise delineation remained uncertain and was defined as either 15pter leads to 15q12::15q12 leads to 15pter or 15pter leads to 15q11::15q13 leads to 15pter. Analysis with various techniques of the satellite regions of the bisatellited chromosomes demonstrated maternal derivation in six and paternal derivation in one of the seven families. A non-sister chromatid exchange between the two homologous chromosomes 15 is considered a likely origin of the inv dup(15) in the cases with maternal derivation; in the only case of paternal derivation, however, the abnormal chromosome originated from one single chromosome 15. The clinical findings confirm that patients with inv dup(15) have mental and developmental retardation and are frequently affected by seizures, while severe physical malformations are absent.