HER-2/neu as a predictive marker in a population of advanced breast cancer patients randomly treated either with single-agent doxorubicin or single-agent docetaxel.

PURPOSE: To evaluate the predictive value of HER-2 in a population of advanced breast cancer patients randomly treated either with single-agent doxorubicin (A) or with single-agent docetaxel (T). EXPERIMENTAL DESIGN: Patients from this study participated in a phase III clinical trial in which doxorubicin or docetaxel was administered for advanced disease. HER-2 was evaluated by IHC. In all positive cases, FISH was used to confirm the HER-2 positive status. The different cohorts of patients identified by HER-2 were examined to assess a possible relationship between HER-2 status and treatment effect. RESULTS: Tumor samples were available for 176 of the 326 patients entered in the clinical trial (54%). HER-2 positivity was observed in 20% of the study population. A statistically significant interaction was found between response rates to the study drugs and HER-2 status, with HER-2 positive patients deriving the highest benefit from the use of T (odds ratio for HER-2 positive patients treated with T = 3.12 (95% CI 1.11-8.80), p = 0.03). The interaction between HER-2 and response rates to A and T was also confirmed by a multivariate analysis. No statistically significant interaction was found between HER-2 and drugs efficacy evaluated in terms of time to progression and overall survival, although in the HER-2 negative cohort A was at least as effective as T in term of overall survival. CONCLUSIONS: These results suggest that in HER-2 positive breast cancer patients docetaxel might be more active than doxorubicin, while in HER-2 negative patients doxorubicin might be at least as effective as docetaxel. Although the present results cannot have an impact on current practice, they allow us to formulate the hypothesis that HER-2 positive breast cancer is a heterogeneous disease with regard to sensitivity to anthracyclines and taxanes, and that this might be dependent upon other molecular markers including the p-53 and topoisomerase II alpha genes. This hypothesis is currently being tested prospectively in two different 'bench to bed-side' clinical trials.

Correlation between topoisomerase-IIalpha gene amplification and protein expression in HER-2 amplified breast cancer.

Topoisomerase-IIalpha (topo-II) is a molecular target for topo-II inhibitors, which makes it a potential predictive marker of responsiveness to these agents. We aim to correlate topo-II gene and protein status on 103 HER-2 amplified breast cancer samples. Paraffin-embedded blocks were screened by FISH for topo-II gene amplification (topo-II: CEP17 ratio >/=1.5; triple probe by Vysis inc.) and analyzed by IHC for topo-II protein expression (continuous variable; clone KiS1) and Ki-67 (positive if >25% of stained cells; clone MIB-1). Topo-II gene amplification was observed in 36.9% (38/103) of the HER-2 amplified study population. HER-2 amplification level (e.g. copy number) was not shown to be predictive for topo-II amplification. The median percentage of topo-II positively stained cells by IHC for topo-II non-amplified and amplified cases were 5% and 10%, respectively. A weak but significant correlation was observed between topo-II gene amplification level and percentage of positively stained cells (Spearman's ranks correlation coefficient of 0.23, p=0.02), the observed correlation being higher in patients with positive staining for Ki-67. Contrary to HER-2, where gene amplification is almost always correlated with protein overexpression in breast cancer, topo-II gene amplification apparently does not always lead to protein overexpression, at least when the latter is evaluated by IHC. Other factors, specifically the tumor proliferation status, may interfere with the topo-II protein status. Although the great majority of topo-II gene aberrations occur in HER-2 positive tumors, the level of HER-2 amplification does not predict for topo-II amplification.

Correlation between complete response to anthracycline-based chemotherapy and topoisomerase II-alpha gene amplification and protein overexpression in locally advanced/metastatic breast cancer.

UNLABELLED: Anthracycline-based regimens are among the most active but also with greater risk of both acute and long-term side effects, namely cardiotoxicity. Predictive markers of response to anthracyclines are therefore essential. Topoisomerase-IIalpha (topo-II) is the target of anthracyclines and preliminary data suggest its promising role as a predictive marker of sensitivity to these drugs. After screening a population of about 350 patients with locally advanced or metastatic breast cancer, two subgroups were selected for the present analysis: a study group (31 patients), composed of 14 complete responders (CR-a) and 17 true non-responders (PD-a) to anthracycline-based CT, and a control group (28 patients), composed of 7 CR (CR-t) and 21 true non-responders (PD-t) to taxane-based CT. True non-responders were defined as progressive disease (PD) within the first three cycles of CT. Archival tumor samples of these patients were collected, biological markers evaluated and their status correlated with response to therapy. HER-2 and topo-II gene status were evaluated by FISH (Vysis multi-color probe-positivity cut-off: >/=2 ratio for HER-2 and >/=1.5 for topo-II), topo-II protein was evaluated by IHC (positivity cut-off >10%). All cases in which HER-2 gene was non-amplified did not show topo-II gene aberrations. No association was found between HER-2 gene amplification and response to anthracyclines (5/14 (36%) CR and 5/17 (29%) PD to anthracycline-based CT were HER-2+). The topo-II gene was amplified in 3/14 (21%) CR but only in 1/17 (6%) PD to anthracyclines. Amplification of the topo-II gene was seen in 1/7 (14%) CR and in 3/21 (14%) PD to a taxane-based CT. Topo-II protein was overexpressed in 6/11 (55%) CR and in 2/17 (12%) PD to anthracyclines, while in the control group, overexpression was seen in 5/7 (71%) CR and 8/20 (40%) PD. IN CONCLUSION: i) HER-2 gene amplification did not seem to be correlated with response to anthracyclines. ii) Both topo-II gene amplification and protein overexpression seem to correlate with response to anthracyclines, although other factors, such as p53 and cell proliferation, are most likely to be involved. iii) The role of combined evaluation of several relevant markers and of potential 'molecular signatures' are currently being evaluated in prospective randomized clinical trials.

Comparison of topoisomerase-IIalpha gene status between primary breast cancer and corresponding distant metastatic sites.

BACKGROUND: Topoisomerase-IIalpha (topo-IIalpha) is a key enzyme in DNA replication and a molecular target for anticancer drugs called topoisomerase-II inhibitors, such as anthracyclines. Its value as a predictive marker of responsiveness to these cytotoxic drugs is currently being evaluated with promising results. However, even in the metastatic setting, the choice of treatment is based on the biologic characteristics of the primary tumor. Few data are available regarding the expression of biological markers between the primary tumor and the corresponding distant metastases. METHODS: Topo-IIalpha gene status was evaluated in 29 breast cancer patients in which a primary tumor sample and a corresponding metastatic sample were both available. Fluorescent in situ hybridization (FISH) with the Vysis triple probe (Vysis multi-color topo-IIalpha spectrum orange, Her-2 spectrum green and CEP17 spectrum aqua probe) was used, which allowed the concomitant evaluation of HER-2 gene status. RESULTS: As previously reported, topo-IIalpha gene aberrations are always associated with HER-2 gene amplification; indeed no topo-IIalpha gene aberrations have been observed in the HER-2 negative tumors. Conversely, 38.5% (five patients) of the HER-2 positive primary breast tumors (13 patients) were topo-IIalpha amplified, while 61.5% (eight patients) had a normal topo-IIalpha gene. No topo-IIalpha gene deletion was found in our series. Topo-IIalpha gene amplification in the primary tumor was always associated with amplification in the corresponding metastases, and no metastases with topo-IIalpha gene amplification were seen without amplification in the primary tumor. Furthermore, the amplification level of topo-IIalpha (i.e., ratio topo-IIalpha:CEP17) remained unchanged in primary and metastatic sites. CONCLUSION: Despite the low number of patients, our results seem to indicate that topo-IIalpha gene status evaluation in the primary breast tumor accurately reflects its status in the corresponding distant metastases.

Effect of the benzene metabolite, hydroquinone, on interleukin-1 secretion by human monocytes in vitro.

Decreased interleukin-1 (IL-1) production by mononuclear phagocytes has been shown to contribute to benzene myelotoxicity in animals. The study presented here was designed to examine the relevance of this mechanism in humans. Fresh human blood monocytes were exposed to 0.001-10 microM hydroquinone (HQ) and assessed for their ability to release IL-1 alpha and IL-1 beta in response to a stimulation with endotoxin. Both cytokines were measured by specific ELISA. Exposure of human monocytes to micromolar concentrations of HQ for 2 hr resulted in a dose-dependent reduction of IL-1 secretion. For both IL-1 alpha and IL-1 beta, the decreases were statistically significant at concentrations of 5 microM and above. HQ also inhibited RNA and protein synthesis in a dose-dependent manner, with 50% inhibitory concentrations of 21 +/- 11 and 10 +/- 9 microM, respectively. Furthermore, monocytes treated with 5 microM HQ also displayed a reduced total protein content when compared with control cells. These data suggest that the reduction of IL-1 production caused by HQ results from a global impairment of monocyte essential functions such as transcription or translation. Taken as a whole, our results support a mechanism whereby HQ may contribute to the myelotoxicity of benzene in humans by inhibiting the production by mononuclear phagocytes of cytokines involved in the regulation of hematopoiesis.