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Comparative Study
. 2010 Oct;89(2):140-8.
doi: 10.1016/j.yexmp.2010.05.002. Epub 2010 May 21.

Expression of leukemia/lymphoma-related factor (LRF/POKEMON) in human breast carcinoma and other cancers

Anshu Aggarwal  1 , William J Hunter 3rd, Himanshu Aggarwal, Edibaldo D Silva, Mary S Davey, Richard F Murphy, Devendra K Agrawal
Affiliations
Comparative Study

Expression of leukemia/lymphoma-related factor (LRF/POKEMON) in human breast carcinoma and other cancers

Anshu Aggarwal et al. Exp Mol Pathol. 2010 Oct.

Abstract

The POK family of proteins plays an important role in not only embryonic development and cell differentiation, but also in oncogenesis. Leukemia/lymphoma-related factor (LRF) belongs to the POK family of transcriptional repressors and is also known as POK erythroid myeloid ontogenic factor (POKEMON), which binds to short transcripts of HIV-1 (FBI-1) and TTF-1 interacting peptide (TIP21). Its oncogenic role is known only in lymphoma, non-small cell lung carcinoma, and malignant gliomas. The functional expression of LRF in human breast carcinoma has not yet been confirmed. The aim of this study was to investigate and compare the expression of LRF in human breast cancer tissues and other human tumors. The expression of LRF mRNA transcripts and protein was observed in twenty human benign and malignant breast biopsy tissues. Expression of LRF was observed in several formalin-fixed tissues by immunohistochemistry and immunofluorescence. All malignant breast tissues expressed mRNA transcripts and protein for LRF. However, 40% and 15% benign breast biopsy tissues expressed LRF mRNA transcripts and protein, respectively. The overall expression of LRF mRNA transcripts and total protein was significantly more in malignant breast tissues than the benign breast tissues. LRF expression was also observed in the nuclei of human colon, renal, lung, hepatocellular carcinomas and thymoma tumor cells. In general, a significantly higher expression of LRF was seen in malignant tissues than in the corresponding benign or normal tissue. Further studies are warranted to determine the malignant role of LRF in human breast carcinoma.

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Figures

Figure 1
Figure 1. Expression of LRF and its mRNA transcripts in human benign and malignant breast biopsy tissues
A - Representative samples of LRF mRNA transcripts expression by RT-PCR with densitometric analysis. B - Representative samples of LRF protein expression by western blotting with densitometric analysis. C - Densitometric analysis of all twenty samples indicating significantly higher expression of LRF mRNA and protein in malignant tissues than in the benign tissues. (*p<0.05; **p<0.01)
Figure 2
Figure 2. Immunohistochemical expression of LRF in representative human breast biopsy tissues
DAB was used as a chromogen and hematoxylin as counterstain (200x).
Figure 3
Figure 3. LRF expression in malignant and normal adjacent tissues of a patient with breast cancer
A - Immunohistochemical expression of LRF. Sections were stained with DAB and counterstained using hematoxylin. B - Immunofluoresence of LRF expression using goat anti-rabbit Cy2 as the secondary antibody, C - DAPI (blue) was used to stain nuclei (400x).
Figure 4
Figure 4. Immunohistochemical expression of LRF in various breast diseases
DAB was used as a chromogen and counterstained with hematoxylin. Representative tissues from each disease are shown (200x – 400x).
Figure 5
Figure 5. Immunofluorescence of LRF expression in breast diseases
Left Panels - Immunofluoresence using goat anti-rabbit Cy2 as the secondary antibody showing LRF expression, Right Panels - DAPI (blue) was used to a nuclear counterstain (200x – 400x).
Figure 6
Figure 6. Immunohistochemical expression of LRF in various carcinomas and corresponding normal tissues
DAB was used as a chromogen and hematoxylin as a counterstain. Representative samples from the array are shown (200x – 400x).
Figure 7
Figure 7. Immunofluorescence of LRF expression in various carcinomas and corresponding normal tissues
Left Panels - Immunofluoresence using goat anti-rabbit Cy2 as the secondary antibody showing LRF expression, Right Panels - DAPI (blue) was used to a nuclear counterstain. Representative samples from the array are shown (200x).
See this image and copyright information in PMC

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