P13: THE EFFECT OF PEGFILGRASTIM ON COMPLETE BLOOD COUNT IN COLORECTAL CANCER PATIENTS TREATED WITH FOLFOX OR FOLFIRI CHEMOTHERAPY

Purpose of Study

In both FOLFOX and FOLFIRI regimens used for colorectal cancer, the 5-FU is infused over 46 hours every 14 days. Given the 10–20% risk of neutropenic fever, these regimens may be given with pegfilgrastim support. There is evidence to support its use for 21 day cycles, but no phase III trials demonstrating its efficacy and safety for regimens given every 14 days, a potential concern, given the hypothesis that the hematopoietic stem cells mobilized by pegfilgrastim into the peripheral blood may undergo cell cycle arrest, apoptosis and death while under effect of chemotherapy. Pegfilgrastim regulates the proliferation, differentiation, and survival of the myeloid lineage. It mobilizes hematopoietic progenitor cells in the peripheral circulation, has a long half-life, and is given on day 4 of 14-day infusional 5-FU based regimens. Given the fact that cytotoxic chemotherapy is administered on day 11 after pegfilgrastim, we performed a retrospective study evaluating the correlation between decrease in complete blood count and chemotherapy administered at 11 day intervals after pegfilgrastim.

Methods Used

The medical records of colorectal cancer patients were reviewed from 2003–2013. Data collected included age, stage, ethnicity, complete blood count, chemotherapy, and use of pegfilgrastim.

Summary of Results

Data from 50 eligible charts was collected. Twenty one patients were treated with chemotherapy and pegfilgrastim, 29 patients had chemotherapy alone. Prior to chemotherapy, both groups had a mean leukocyte count of 6.6×109/L and 6.8×109/L and a mean platelet count of 313,000/mm3 and 255,000/mm3 respectively. At 9 months mean leukocyte counts were 6.3×109/L and 5.4×109/L and the mean platelet counts were 186,000/mm3 and 170,000/mm3 respectively. At 24 months, the mean leukocyte counts were 6.7×109/L and 5.7×109/L and the mean platelet counts were 220,000/mm3 and 196,000 mm3 respectively.

Conclusions

When given on day 4 of a 14 day cycle, there was no effect of pegfilgrastim on complete blood counts in this small retrospective cohort study; finding a more subtle effect would require a larger sample size.

P6: CIRCULATING MICRORNA PATTERN DEFINES A BIOLOGICALLY DISTINCT BREAST CANCER PATTERN IN BLACK (B) WOMEN RELATIVE TO ONE CCCURRING IN WHITE (W) WOMEN

Purpose of Study

Black women with triple negative breast cancer have 46% lower survival rates attributed to differences in tumor biology. We analyzed presurgical plasma microRNA of white (W) and black (B) women with TNBC enrolled in our breast ovarian tissue bank between 2004 and 2014.

Aims

Detect microRNA patterns in pre-surgical plasma of TNBC W or B Analyze differences by integrated approach to detect pathways differentially activated in the two groups.

Methods Used

Between 2004 and 2014 we investigated patterns of plasma miRNAs collected before, after surgery, during and after chemotherapy in 67 patients presenting for surgery for breast cancer (W=44 & B=44) and 25 age and race matched normal controls. Two-sample t-test was used for all 2-sample comparison and ANOVA followed by Benjamin Hochberg post-hoc test to compare the mean response between subject factors of interest. All tests were 2-tailed and results with a p<0.05 were considered statistically significant. Coremine was used to identify datasets in breast cancer microarray with emphasis on our differentially expressed circulating miRs.

Summary of Results

Mean age cancer 48 (range 35–78), control 44 (range 35–67): B patients did not express over 70% of pre-surgical plasma miRs over-expressed in the W pre-surgical plasma. Black patients had lower expression of MiRs: −16-5p, −484, −126, −150-5p, −142-3p; −30c-5p, −186-5p, 139-5p. Samples from white patients overexpressed miRs−126, −150-5p, −142-3p; −30c-5p, −186-5p, 139-5p compared to healthy controls. These miRs significantly suppressed in blacks p<0.05.

Coremine text mining suggests differentially regulated microRNA are involved in mitochondrial quality control and biogenesis.

Conclusions

Deregulation in circulating miRs between B and W patients point to pathways involved in mitochondrial fission and fusion. Aberrant mitochondria biogenesis was reported as mechanism for cancer stem cell survival and detrimental to innate immunity. Such pathways could explain the lower survival seen in black breast cancer patients.

Molecular characterization of 39 de novo sSMC: contribution to prognosis and genetic counselling, a prospective study

Small supernumerary marker chromosomes (sSMCs) are structurally abnormal chromosomes that cannot be characterized by karyotype. In many prenatal cases of de novo sSMC, the outcome of pregnancy is difficult to predict because the euchromatin content is unclear. This study aimed to determine the presence or absence of euchromatin material of 39 de novo prenatally ascertained sSMC by array-comparative genomic hybridization (array-CGH) or single nucleotide polymorphism (SNP) array. Cases were prospectively ascertained from the study of 65,000 prenatal samples [0.060%; 95% confidence interval (CI), 0.042-0.082]. Array-CGH showed that 22 markers were derived from non-acrocentric markers (56.4%) and 7 from acrocentic markers (18%). The 10 additional cases remained unidentified (25.6%), but 7 of 10 could be further identified using fluorescence in situ hybridization; 69% of de novo sSMC contained euchromatin material, 95.4% of which for non-acrocentric markers. Some sSMC containing euchromatin had a normal phenotype (31% for non-acrocentric and 75% for acrocentric markers). Statistical differences between normal and abnormal phenotypes were shown for the size of the euchromatin material (more or less than 1 Mb, p = 0.0006) and number of genes (more or less than 10, p = 0.0009). This study is the largest to date and shows the utility of array-CGH or SNP array in the detection and characterization of de novo sSMC in a prenatal context.