Abstract PD04-09: Multiple Biomarker Expression in Circulating Tumor Cells from Metastatic Breast Cancer Patients

Background: Numeration of circulating tumor cells, CTCs, from metastatic breast cancer (MBC) patients (pts) is predictive of outcome. Biomarker characterization of CTCs may be a useful adjunctive guide for personalized targeted and systemic treatment (Rx) selection.

Method: A multimarker assay was used to simultaneously quantify expression of HER2, ER and ERCC1. A fast laser scanning instrument was used for sensitive location of CTCs on large glass substrates. CTCs are identified using automated digital microscopy by morphology, the presence of cytokeratin and a nucleus, and the absence of CD45. At the COHCC pts with newly diagnosed/progressing MBC were accrued. Blood samples (10 ml) were procured prior to initiating systemic Rx and at subsequent 3 month intervals and sent to PARC for analysis. Cell lines with expression of each marker were used for normalization of the cell intensities. Sample scores were derived from the percentage of CTCs expressing the marker and the average expression level.

Results: The multiple-marker assay was done on CTCs at repeat time points and results were compared to findings from the original primary BCs (P) and biopsied metastases (M) in 30 and 20 MBC pts respectively. While P and M tissue scores were concordant for HER2, the CTC score was discordant in 58% of the samples; HER2 expression changed during Rx in 19% of pts. While the status for ERCC1 was discordant between P and M tissue in 13% of the pts, CTCs scores were discordant with P and M tumors in 63% and 67% of the patients respectively, and CTC expression status changed during Rx in 15% and 7% of pts respectively. While the status for ER was discordant between P and M tissue in 15% of the pts, CTC scores were discordant from the P and M tumors in 42% and 71% of pts respectively, and CTC ER status changed in 7% and 17% respectively of pts during Rx.

Conclusions: Significant discordances in expression level of ER, HER2 andERCC 1 was observed between CTCs, and both primary and metastatic BC tissue. Changes in CTC expression patterns were also observed during the course of Rx for all three markers. Correlation of CTC biomarker expression patterns and changes with response to Rx therapy is ongoing to validate medical significance. Multimarker testing may ultimately lead to improvements in personalized Rx for pts with MBC.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD04-09.

Multiple biomarker expression in circulating tumor cells (CTCs) from locally advanced/inflammatory (LA/IBC) and metastatic breast cancer (MBC) patients (pts)

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Background: Numeration of CTCs from MBC pts is predictive of outcome. Quantitative changes in CTC-s are currently tested for their potential to monitor therapy (Rx). Biomarker characterization of CTCs may be a useful adjunctive guide for Rx selection. Methods: At the COHCC between May 1, 2008 and December 31, 2008, consecutively treated pts with LABC/IBC, or with newly diagnosed/progressing MBC were accrued. Blood samples (20–30 mL) were procured prior to initiating neoadjuvant (neo)Rx (LABC and IBC patients) or systemic Rx (MBC), and were sent to PARC for analysis. A novel high-speed scanning instrument located CTCs from cytokeratin (CK) labeling enabling high resolution images to be selectively acquired using digital microscopy. From these images, CTCs were identified by CK, DAPI (nuclear marker) and CD45, and protein expression levels were determined for HER-2, estrogen receptor (ER), Excision repair cross-complementation group 1 (ERCC1), and EGFR. Cell lines with expression of each marker were used for normalization of the cell intensities, and a scoring system was used to account for relative number and expression levels of markers on the CTCs. Results: Twenty-seven pts with LABC, 4 pts with IBC, and 11 pts with MBC were enrolled. We have observed CTCs prior to initiating neoRx in all pts with IBC relative to 39% of all LABC/IBC cases, and in 57% of pts (n:14) with HER-2+ primary BC versus 24% (n = 17) with HER-2- BC . ER status, size, or grade did not predict for CTC detection. Numeration of CTCs was seen in 45% of pts with MBC. Expression of EGFR and ERCC1 was detected in 3 of 4, and 2 of 4 tested CTC samples from MBC cases. Expression of HER-2 and ER was observed on 1 of 3 and 3 of 4 CTC samples; there was discrepancy between the CTC expression profile and HER-2 and ER status of the primary BC in one case each. Conclusions: Detecting multiple markers in CTCs from pts with MBC is feasible, and similar testing in LABC/IBC patients is needed. Such multiplex testing may allow for more personalized Rx for pts with LABC/IBC and MBC.

No significant financial relationships to disclose.

High-speed detection of occult tumor cells in peripheral blood

Although detection of tumor cells in peripheral blood using imitiunocytochemistry and optical scanning is a promising method for screening and monitoring cancer, it poses a major technical challenge due to the extremely low tumor cell concentration in blood. The preferred detection method - digital microscopy - is far too slow for analysis of the large numbers of cells required for statistical validity. We describe here a novel prescan instrument that rapidly identifies a small number of candidates for subsequent examination by digital microscopy to determine if they are genuine tumor cells. The prescan is 500 times faster than digital microscopy and yet has a similar sensitivity. The high prescan speed is accomplished by trading resolution for field of view. The resolution of the prescan is determined by the laser spot size of about 10 microns. While this resolution is much coarser than the submicron resolution of microscopes, it is still sufficient for detecting fluorescent cells because it matches the size of a typical cell. The wide field of view and high scan rate are enabled by a novel application of fiber optics.

Low vaccination levels of US preschool and school-age children. Retrospective assessments of vaccination coverage, 1991-1992

OBJECTIVE

To obtain estimates on (1) the percentage of children who were up-to-date on the recommended childhood vaccination series, (2) the percentage of children who were age-appropriately immunized, and (3) coverage levels by individual vaccines.

DESIGN

Vaccination levels were estimated by conducting retrospective immunization coverage surveys of the school health records of children entering kindergarten or first grade in the 1990-1991 or 1991-1992 school year. A multistage cluster survey design was used.

SETTING

Survey sites were selected from among the 60 largest urban areas in the United States. One small city and one rural area were selected for comparison.

RESULTS

By their second birthday, 11% to 58% (median, 44%) of the children were fully vaccinated. Stricter measurement criteria lowered coverage levels further. Completed series levels at school entry were 71% to 96% (median, 87%).

CONCLUSIONS

Vaccination levels at the second birthday were far below the goal for the year 2000. All health providers need to administer vaccines according to the recommended schedule.