Biomarkers do seem to indicate a change in T-cell phenotype over time (loss of memory T cells), which does correlate with responsiveness to MTX [ 14].
However, we believe that these signatures could represent a dynamic descriptor of pathway activity compared to EGFR protein status alone, which does not predict responsiveness to EGFR inhibitors [ 66- 68].
Results from the first 3,533 patients on the two monotherapy arms with ER+ tumors (by central assessment) and centrally assessed PgR and HER2 confirmed the results reported above from the local assessment of receptor status [ 18, 21], indicating that PgR status in ER+ tumors does not predict responsiveness to letrozole when compared with tamoxifen.
Several factors are noteworthy by their absence as response determinants: these include absolute levels of ERK or AKT (presumably they are present in excess), and basal RTK phosphorylation (except in the aforementioned case of pErbB2), implying that even high autocrine activation does not block responsiveness to additional, exogenous ligand.
Although the CTC levels determined in this study do not allow us to clearly conclude that the inflammatory cytokine-HPA axis feedback is dysregulated in obesity, the results do suggest reduced responsiveness to high levels of IL-6 in corticosterone release in the obese Zucker rats.
Unlike heat shock at 33°C, a 27°C heat shock did not alter responsiveness to the ACh esterase inhibitor, aldicarb (data not shown).
Devon [ 63] compared the SF-36 with three other commonly used instruments, and found that it did not demonstrate responsiveness to change in functional status.
While the different classes do not predict responsiveness to anthracycline-based or mitomycin-based chemotherapy [ 11], tumours belonging to the different classes may be subject to different targeted, or tailored, therapeutic approaches.
39 In a study of children aged 3 36 months, those infected with rhinovirus showed fewer relapses when treated with oral prednisone compared to placebo, suggesting that rhinovirus did not impair responsiveness to steroids.
This observation agrees with previous results showing that BCAR1 and BCAR3 cell lines generated by retroviral insertion mutagenesis had all lost ERα protein expression and did not acquire responsiveness to EGF [ 16, 17].
