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miR-21 Expression in Pregnancy-Associated Breast Cancer: A Possible Marker of Poor Prognosis.

Walter BA, Gómez-Macias G, Valera VA, Sobel M, Merino MJ - J Cancer (2011)

Bottom Line: We then analyzed protein expression for PTEN, BCL2 and PDCD4 as miR-21 target genes by IHC, and finally correlated the results with patients' clinicopathological features.Significant overexpression of miR-21 in PABC tumors compared to normal adjacent tissue was found.Overexpression of miR-21 was frequently found in high grade tumors with loss of hormone receptor expression and was significantly associated with positive lymph nodes (p=0.025).In PABC patients, PTEN, BCL2 and PDCD4 target protein expression was decreased in 80%, 76% and 40% respectively.

View Article: PubMed Central - PubMed

Affiliation: 1. Laboratory of Pathology, National Institutes of Health, National Cancer Institute, Bethesda, MD, USA;

ABSTRACT

Aims: microRNAs (miRNAs) are a class of small noncoding RNAs that can act as key modulators in tumorigenesis-related genes. Specifically, it has been suggested that miR-21 overexpression plays a role in the development and progression of breast cancer. So far, the role of miRNAs in pregnancy-associated breast cancer (PABC) has not been investigated.

Methods and results: We evaluated miR-21 expression by quantitative RT-PCR in 35 patients, 25 with PABC and 10 control breast cancer cases not pregnancy-associated with similar clinicopathological features. We then analyzed protein expression for PTEN, BCL2 and PDCD4 as miR-21 target genes by IHC, and finally correlated the results with patients' clinicopathological features.Significant overexpression of miR-21 in PABC tumors compared to normal adjacent tissue was found. Overexpression of miR-21 was frequently found in high grade tumors with loss of hormone receptor expression and was significantly associated with positive lymph nodes (p=0.025). In PABC patients, PTEN, BCL2 and PDCD4 target protein expression was decreased in 80%, 76% and 40% respectively.

Conclusion: Our study supports the involvement of miR-21 in breast cancer progression and metastasis formation in PABC implying a role of this miRNA as a marker for poor prognosis in PABC patients.

No MeSH data available.


Related in: MedlinePlus

A) miR-21 expression in PABC samples with metastatic lymph nodes. B-D) Impact of some clinicopathological variables on overall survival for PABC patients.
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Figure 2: A) miR-21 expression in PABC samples with metastatic lymph nodes. B-D) Impact of some clinicopathological variables on overall survival for PABC patients.

Mentions: The median fold-change for all PABC cases was 5-fold. This value was used then to divide patients into two groups: miR-21 moderate expressers (n=11, 31%) and miR-21 high expressers (n=13, 37%). Since all cases showed overexpression of miR-21 compared to normal tissue, no low-expressers category was included. Tumors with a high overexpression level of miR-21 correlated positively with the presence of metastatic lymph nodes (p=0.025, Figure 2A). The other clinicopathological features of the PABC cases did not significantly correlate with miR-21 expression levels (Table 2).


miR-21 Expression in Pregnancy-Associated Breast Cancer: A Possible Marker of Poor Prognosis.

Walter BA, Gómez-Macias G, Valera VA, Sobel M, Merino MJ - J Cancer (2011)

A) miR-21 expression in PABC samples with metastatic lymph nodes. B-D) Impact of some clinicopathological variables on overall survival for PABC patients.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3039223&req=5

Figure 2: A) miR-21 expression in PABC samples with metastatic lymph nodes. B-D) Impact of some clinicopathological variables on overall survival for PABC patients.
Mentions: The median fold-change for all PABC cases was 5-fold. This value was used then to divide patients into two groups: miR-21 moderate expressers (n=11, 31%) and miR-21 high expressers (n=13, 37%). Since all cases showed overexpression of miR-21 compared to normal tissue, no low-expressers category was included. Tumors with a high overexpression level of miR-21 correlated positively with the presence of metastatic lymph nodes (p=0.025, Figure 2A). The other clinicopathological features of the PABC cases did not significantly correlate with miR-21 expression levels (Table 2).

Bottom Line: We then analyzed protein expression for PTEN, BCL2 and PDCD4 as miR-21 target genes by IHC, and finally correlated the results with patients' clinicopathological features.Significant overexpression of miR-21 in PABC tumors compared to normal adjacent tissue was found.Overexpression of miR-21 was frequently found in high grade tumors with loss of hormone receptor expression and was significantly associated with positive lymph nodes (p=0.025).In PABC patients, PTEN, BCL2 and PDCD4 target protein expression was decreased in 80%, 76% and 40% respectively.

View Article: PubMed Central - PubMed

Affiliation: 1. Laboratory of Pathology, National Institutes of Health, National Cancer Institute, Bethesda, MD, USA;

ABSTRACT

Aims: microRNAs (miRNAs) are a class of small noncoding RNAs that can act as key modulators in tumorigenesis-related genes. Specifically, it has been suggested that miR-21 overexpression plays a role in the development and progression of breast cancer. So far, the role of miRNAs in pregnancy-associated breast cancer (PABC) has not been investigated.

Methods and results: We evaluated miR-21 expression by quantitative RT-PCR in 35 patients, 25 with PABC and 10 control breast cancer cases not pregnancy-associated with similar clinicopathological features. We then analyzed protein expression for PTEN, BCL2 and PDCD4 as miR-21 target genes by IHC, and finally correlated the results with patients' clinicopathological features.Significant overexpression of miR-21 in PABC tumors compared to normal adjacent tissue was found. Overexpression of miR-21 was frequently found in high grade tumors with loss of hormone receptor expression and was significantly associated with positive lymph nodes (p=0.025). In PABC patients, PTEN, BCL2 and PDCD4 target protein expression was decreased in 80%, 76% and 40% respectively.

Conclusion: Our study supports the involvement of miR-21 in breast cancer progression and metastasis formation in PABC implying a role of this miRNA as a marker for poor prognosis in PABC patients.

No MeSH data available.


Related in: MedlinePlus