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Estrogen receptor alpha (ER alpha) mRNA copy numbers in immunohistochemically ER alpha-positive-, and negative breast cancer tissues.

Poola I, Yue Q - BMC Cancer (2007)

Bottom Line: This method is not quantitative, highly subjective and requires large amount of tumor tissue, therefore, cannot be applied to sterotactic and ultrasound guided biopsy samples.However, it is not known how the mRNA copy numbers correlate to IHC positive and negative status.ROC analysis of the data gave an area of 0.8967 under the curve.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Howard University School of Medicine, Washington, DC 20059, USA. ipoola@howard.edu

ABSTRACT

Background: The presence of ERalpha is the basis for treating breast cancer patients with targeted molecular therapies that block estrogen stimulation of breast cancer cell division. To select patients for the above therapies, currently, the ERalpha presence in breast cancer tissues is determined in clinical laboratories by microscopically scoring the slides subjected to immunohistochemistry (IHC). This method is not quantitative, highly subjective and requires large amount of tumor tissue, therefore, cannot be applied to sterotactic and ultrasound guided biopsy samples. To circumvent these problems, we previously developed quantitative real-time PCR based molecular assay that can be applied to determine mRNA copies of ERalpha in picogram amounts of total RNA from tumor samples. However, it is not known how the mRNA copy numbers correlate to IHC positive and negative status.

Methods: In the current study we determined the copy numbers of ERalpha mRNA by Q RTPCR in breast cancer tissues that were graded as ERalpha-positive and negative by 1) IHC and 2) functional estrogen binding assay and statistically analyzed the data.

Results: We demonstrate here that ERalpha mRNA copy numbers are not significantly different in tissues that are graded as positive by IHC and ligand binding assays. We establish here a cut of value of 5 x 106 copies per 1010 mRNA copies of GAPDH with an Odds Radio of 39.4, Sensitivity of 0.81 and Specificity of 0.90 in breast cancer tissues that are negative for ERalpha protein by IHC and estrogen binding assays. ROC analysis of the data gave an area of 0.8967 under the curve.

Conclusion: We expect that the cut off values determined here will be highly significant for applying molecular assay in the place of IHC in clinical laboratories for evaluating the presence of ERalpha for prognostic and therapeutic purposes.

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Related in: MedlinePlus

Receiver Operating Characteristic curve drawn using the data on ERα mRNA copy numbers is shown.
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Figure 2: Receiver Operating Characteristic curve drawn using the data on ERα mRNA copy numbers is shown.

Mentions: We applied the above cut off value and determined the Sensitivity (percentage of samples that showed higher copy numbers than the cut off value of 5 × 106 copies per 1010 GAPDH copies in IHC positive tissues) and Specificity (percentage of samples that showed less than 5 × 106 copies per 1010 GAPDH copies in IHC negative tissues) and the values obtained were 0.81 and 0.90 respectively. We also determined Receiver Operating Characteristics using S-PLUS software and the ROC curve generated is shown in Figure 2. The area under the ROC curve, 0.89675, shows that the molecular assay clearly distinguishes the positives by IHC or estrogen binding from the negative tissues.


Estrogen receptor alpha (ER alpha) mRNA copy numbers in immunohistochemically ER alpha-positive-, and negative breast cancer tissues.

Poola I, Yue Q - BMC Cancer (2007)

Receiver Operating Characteristic curve drawn using the data on ERα mRNA copy numbers is shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1851709&req=5

Figure 2: Receiver Operating Characteristic curve drawn using the data on ERα mRNA copy numbers is shown.
Mentions: We applied the above cut off value and determined the Sensitivity (percentage of samples that showed higher copy numbers than the cut off value of 5 × 106 copies per 1010 GAPDH copies in IHC positive tissues) and Specificity (percentage of samples that showed less than 5 × 106 copies per 1010 GAPDH copies in IHC negative tissues) and the values obtained were 0.81 and 0.90 respectively. We also determined Receiver Operating Characteristics using S-PLUS software and the ROC curve generated is shown in Figure 2. The area under the ROC curve, 0.89675, shows that the molecular assay clearly distinguishes the positives by IHC or estrogen binding from the negative tissues.

Bottom Line: This method is not quantitative, highly subjective and requires large amount of tumor tissue, therefore, cannot be applied to sterotactic and ultrasound guided biopsy samples.However, it is not known how the mRNA copy numbers correlate to IHC positive and negative status.ROC analysis of the data gave an area of 0.8967 under the curve.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Howard University School of Medicine, Washington, DC 20059, USA. ipoola@howard.edu

ABSTRACT

Background: The presence of ERalpha is the basis for treating breast cancer patients with targeted molecular therapies that block estrogen stimulation of breast cancer cell division. To select patients for the above therapies, currently, the ERalpha presence in breast cancer tissues is determined in clinical laboratories by microscopically scoring the slides subjected to immunohistochemistry (IHC). This method is not quantitative, highly subjective and requires large amount of tumor tissue, therefore, cannot be applied to sterotactic and ultrasound guided biopsy samples. To circumvent these problems, we previously developed quantitative real-time PCR based molecular assay that can be applied to determine mRNA copies of ERalpha in picogram amounts of total RNA from tumor samples. However, it is not known how the mRNA copy numbers correlate to IHC positive and negative status.

Methods: In the current study we determined the copy numbers of ERalpha mRNA by Q RTPCR in breast cancer tissues that were graded as ERalpha-positive and negative by 1) IHC and 2) functional estrogen binding assay and statistically analyzed the data.

Results: We demonstrate here that ERalpha mRNA copy numbers are not significantly different in tissues that are graded as positive by IHC and ligand binding assays. We establish here a cut of value of 5 x 106 copies per 1010 mRNA copies of GAPDH with an Odds Radio of 39.4, Sensitivity of 0.81 and Specificity of 0.90 in breast cancer tissues that are negative for ERalpha protein by IHC and estrogen binding assays. ROC analysis of the data gave an area of 0.8967 under the curve.

Conclusion: We expect that the cut off values determined here will be highly significant for applying molecular assay in the place of IHC in clinical laboratories for evaluating the presence of ERalpha for prognostic and therapeutic purposes.

Show MeSH
Related in: MedlinePlus