Writing the Methods and Results Sections
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coefficients with the weakly invasive BC consensus of 0.95. The GEPs of BRF71T1, HBL-100, SUM159PT, and SUM1315mo2 cells were most similar to the highly invasive BC consensus, with correlation coefficients ranging from 0.82 to 0.88 (Fig. 3B). Thus, each of these cell lines could be classified as weakly or highly aggressive based upon its correlation with the weakly or highly invasive BC GEP. In contrast, the cells derived from reduction mammoplasty (that is, 48RS and 184B5) had GEPs that were more similar to the MCF10A GEP than to either the weakly or highly invasive BC consensus GEP (compare Fig. 3, A and B), as seen by the low number of genes with expression ratios that differed from MCF10A by more than 2-fold. One notable exception was the elevated level of osteonectin mRNA (#19) found in the 48RS, which was also observed in the very similar GEPs of two other cell strains derived from reduction mammoplasties (data not shown). The correlation between 48RS and the highly invasive BC GEP decreased from 0.59 to 0.36 when osteonectin was excluded from the calculation. We were surprised that the DCIS-derived cell line SUM102PT had a GEP that was also more similar to the reference MCF10A than to either consensus, although we detected significant differences in the expression of other genes analyzed by the cDNA arrays (data not shown). (Adapted with permission from Zajchowski DA et al. Identification of gene expression profiles that predict the aggressive behavior of breast cancer cells. Cancer Res 61:5168 – 5178, 2001.) Example 2: In the following example, the authors have speculated about 2 findings in the Results section (bold passages). This is OK because the speculation is brief and focuses on specific findings.
Confirmation of Comparative Genomic Hybridization Data by FISH
FISH analysis on touch preparations of six endocrine pancreatic tumors (EPTs) confirmed the comparative genomic hybridization (CGH) results of chromosome arms 9q and 6q (Table 1). Two benign insulinomas without chromosome imbalances (from patients 2 and 3) presented two copies of the centromere and locus-specific probe per nucleus for both chromosome arms in the FISH analysis, indicating that these tumors have a diploid DNA content. . . . The other insulinoma (from patient 11) turned out to harbor two genetically heterogeneous cell populations exhibiting three and four copies of the chromosome 9 probes. Because we blocked repeated sequences with Cot-1 DNA, we could not analyze the centromeric region by CGH, which probably explains the detection of only the 9q34
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