OBJECTIVETo identify genes expressed in the fetal heart that are potentially important for myocardial development and cardiomyocyte proliferation.

METHODSmRNAs from fetal (29 weeks) and adult cardiomyocytes were use for suppression subtractive hybridization (SSH). Both forward (fetal as tester) and reverse (adult as driver) subtractions were performed. Clones confirmed by dot-blot analysis to be differentially expressed were sequenced and analyzed.

RESULTSDifferential expressions were detected for 39 out of 96 (41%) clones on forward subtraction and 24 out of 80 (30%) clones on reverse. For fetal dominating genes, 28 clones matched to 10 known genes (COL1A2, COL3A1, endomucin, HBG1, HBG2, PCBP2, LOC51144, TGFBI, vinculin and PND), 9 clones to 5 cDNAs of unknown functions (accession AK021715, AF085867, AB040948, AB051460 and AB051512) and 2 clones had homology to hEST sequences. For the reverse subtraction, all clones showed homology to mitochondrial transcripts.

CONCLUSIONSWe successfully applied SSH to detect those genes differentially expressed in fetal cardiac myocytes, some of which have not been shown relative to myocardial development.

Aged ; Cells, Cultured ; Collagen ; Collagen Type I ; Collagen Type III ; genetics ; DNA-Binding Proteins ; genetics ; Forkhead Transcription Factors ; Gene Expression ; physiology ; Heart ; embryology ; growth & development ; Heterogeneous-Nuclear Ribonucleoproteins ; genetics ; Humans ; Nerve Tissue Proteins ; genetics ; Nucleic Acid Hybridization ; RNA-Binding Proteins ; Transcription Factors ; Transforming Growth Factor beta ; genetics ; Transforming Growth Factor beta1 ; Vinculin ; genetics

PURPOSE: Proline, glutamic acid, and leucine-rich protein 1 (PELP1), a novel nuclear receptor (NR) co-regulator, is highly expressed in breast cancer. We investigated its expression in breast cancer subtypes, in comparison with other breast markers as well as cancers from different sites. Its prognostic relevance with different subtypes and other NR expression was also examined in breast cancers. MATERIALS AND METHODS: Immunohistochemical analysis was performed on totally 1,944 cancers from six different organs. RESULTS: PELP1 expression rate was the highest in breast cancers (70.5%) among different cancers. Compared to GATA3, mammaglobin and gross cystic disease fluid protein 15, PELP1 was less sensitive than GATA3 for luminal cancers, but was the most sensitive for non-luminal cancers. PELP1 has low expression rate (<20%) in colorectal cancers, gastric cancers and renal cell carcinomas, but higher in lung cancers (49.1%) and ovarian cancers (42.3%). In breast cancer, PELP1 expression was an independent adverse prognostic factor for non-luminal cancers (disease-free survival [DFS]: hazard ratio [HR], 1.403; p=0.012 and breast cancer specific survival [BCSS]: HR, 1.443; p=0.015). Interestingly, its expression affected the prognostication of androgen receptor (AR). AR(pos)PELP1(lo) luminal cancer showed the best DFS (log-rank=8.563, p=0.036) while AR(neg)PELP1(hi) non-luminal cancers showed the worst DFS (log-rank=9.536, p=0.023). CONCLUSION: PELP1 is a sensitive marker for breast cancer, particularly non-luminal cases. However, its considerable expression in lung and ovarian cancers may limit its utility in differential diagnosis in some scenarios. PELP1 expression was associated with poor outcome in non-luminal cancers and modified the prognostic effects of AR, suggesting the potential significance of NR co-regulator in prognostication.
Breast Neoplasms ; Breast ; Carcinoma, Renal Cell ; Colorectal Neoplasms ; Diagnosis, Differential ; Glutamic Acid ; Immunohistochemistry ; Lung ; Lung Neoplasms ; Ovarian Neoplasms ; Phenobarbital ; Prognosis ; Proline ; Receptors, Androgen ; Stomach Neoplasms