Expression of PIK3CA, PTEN mRNA and PIK3CA mutations in primary breast cancer: association with lymph node metastases

Abstract

PurposeHigh activity of the intracellular phosphatidylinositol-3 kinase (PI3K) pathway is common in breast cancer. Here, we explore differences in expression of important PI3K pathway regulators: the activator, phosphatidylinositol-3-kinase catalytic subunit alpha (PIK3CA), and the tumour suppressor, phosphatase and tensin homolog (PTEN), in breast carcinoma tissue and normal breast tissue. Furthermore, we examine whether expression of PIK3CA and PTEN mRNA and occurrence of PIK3CA mutations are associated with lymph node metastases in patients with primary breast cancer.MethodsPaired tissue samples of breast carcinoma and normal breast tissue were obtained from 175 breast cancer patients at the time of primary surgery, of these 105 patients were lymph node positive. Expression of PIK3CA and PTEN mRNA was quantified with Quantitative Real Time PCR. Somatic mutations in exon 9 and exon 20 of the PIK3CA gene were identified by genotyping.ResultsBoth PIK3CA and PTEN mRNA expression was significantly increased in breast carcinoma tissue compared to normal breast tissue (p = 2 × 10-11) and (p < 0.001), respectively. PIK3CA mutations were present in 68 out of 175 patients (39%), but were not associated with PIK3CA expression (p = 0.59). Expression of PIK3CA and PTEN mRNA, and PIK3CA mutations in breast carcinomas were not associated with presence of lymph node metastases.ConclusionsThe expression of PTEN and PIK3CA mRNA is increased in breast carcinoma tissue compared to normal breast tissue, and PIK3CA mutations are frequent in primary breast carcinoma, however these factors were not associated with lymph node metastases.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-464) contains supplementary material, which is available to authorized users.

RNASeq analysis reveals biological processes governing the clinical behaviour of endometrioid and serous endometrial cancers

“…It should be noted that expression levels of the PIK3CA prototype gene and module were found not to correlate with the PIK3CA gene mutation status (Supplementary Fig. 5), which is in agreement with previous reports based on the analysis of breast cancers[21]. Our results support previous reports suggesting that co-occurring mutations and epigenetic aberrations affecting different components of the PI3K pathway may converge on regulation of PTEN expression levels and function in ECs[22].…”

PIK3CA and PTEN Genes Expressions in Breast Cancer

“…The results of PTEN gene expression in this study were contrary to expected, the expression was significantly higher in carcinoma tissue than in normal breast tissue (P<0.001, Z=5.362) where the median value of PTEN expression in breast cancer tissue was 13.76 but in normal tissue was 2.42. The current study showed decreased in PTEN expression in breast tumor tissue in only 16% of patients compared to expression in normal breast tissue, which was similar to Palimaru et al study (Palimaru et al, 2013), it has been reported that low of PTEN mRNA expression in breast carcinoma tissue occurs in only 20% of patients compared to normal breast tissue. In a study at 2018 for measuring PTEN mRNA expression in breast carcinoma tissue and compared to expression in normal breast tissue for 78 breast cancer patients, a reduced PTEN expression in breast carcinoma tissue was found in only 33.3% of patients (Salmani et al, 2018).…”

“…To our knowledge, there is not many studies about PIK3CA gene expression in breast cancer, most studies focused on PIK3CA mutations in breast cancer. PIK3CA expression data in the current study similar to data in the Palimaru et al, (2013) study that showed significantly higher PIK3CA expression in breast carcinoma than in normal breast tissue (p=2x10 -11 ), PIK3CA expression was increased in breast carcinoma in 76% of patients (114/149) whereas in our study the PIK3CA expression was increased in breast carcinoma in 96% of patients (47/50). Also, there was a previous report at 2010 (Aleskandarany et al, 2010) showed PIK3CA high expression in breast tumor tissue with IHC.…”

Regulatory dissection of the CBX5 and hnRNPA1 bi-directional promoter in human breast cancer cells reveals novel transcript variants differentially associated with HP1α down-regulation in metastatic cells

“…We next analysed the relationship between hnRNPA1 , HP1α-V3 and STET mRNA expression in breast cancer samples to see whether this corresponds to observations from breast cancer cell lines. cDNA was prepared from paired tissue samples from 193 patients with breast cancer [ 43 , 44 ]. 81 of the patients had metastases in the lymph nodes.…”

“…After synthesis the cDNA product was diluted with redistilled water to a total volume of 100 μl and stored at −20 °C. For breast cancer samples, cDNA was synthesized from RNA previously isolated from primary normal breast tissue, breast carcinomas and lymph node metastases [ 43 , 44 ]. cDNA was synthesized in a 20 μl reaction mix including 50 μmol/L Oligo(dT), reverse transcriptase (50 units/μL), RNase inhibitors (20 units/μL), 0.4 mmol/L of each dNTP, 1xPCR buffer, and 25 mmol/L MgCL2 (all from Applied Biosystems Inc., CA, USA).…”