This study is the largest to date examining PTEN status in breast cancer and the data suggest that the rate and significance of PTEN status differ between HER2-positive and HER2-negative disease.
The involvement of PTEN in human mammary oncogenesis has been implicated from studies showing that germline PTEN mutation in Cowden disease predisposes to breast cancer, the frequent loss of heterozygosity at the PTEN locus, and reduced PTEN protein levels in sporadic breast cancers.
This scenario is confirmed by extensive numerical simulations and validated by re-analyzing phosphatase and tensin homolog's cross-talk pattern from The Cancer Genome Atlas breast cancer database.
To identify the disease-causing mutations in a cohort of 120 Brazilian women fulfilling criteria for HBOC, we carried out a comprehensive screening of BRCA1/2, TP53 R337H, CHEK2 1100delC, followed by an analysis of copy number variations in 14 additional breast cancer susceptibility genes (PTEN, ATM, NBN, RAD50, RAD51, BRIP1, PALB2, MLH1, MSH2, MSH6, TP53, CDKN2A, CDH1 and CTNNB1).
Increased circulating levels of PTEN and phosphorylated PTEN protein were also observed by immunostaining in patients with breast cancer and precursor breast lesions.
We analysed PI3KCA hot-spot mutations and PTEN immunohistochemical expression in 129 Her2-positive infiltrating BC treated with trastuzumab, including 26 cases treated with neoadjuvant therapy, 48 metastatic infiltrating breast cancer (IBC; MBC) and 55 early-stage IBC, with complete clinical information (mean follow-up 37, 66 and 32 months, respectively).
Our previous study indicated that MEOX1 is a critical molecular target in mesenchymal-like cancer cells in PTEN-deficient Trastuzumab resistant breast cancer.
In this study, we aimed to explore whether PIK3CA mutations and PTEN loss are mutually exclusive mechanisms, correlate with other known clinicopathologic markers, or have clinical implication in breast cancer.
Germ-line PTEN mutations were detected in all of five families with both breast cancer and CD, in one family with juvenile polyposis syndrome, and in one of four families with breast and thyroid tumors.
Therefore, PTEN germline mutations were searched for in a series of 20 unrelated women with breast cancer who also had a personal or familial breast-brain tumour history.
Our results reveal a novel mechanism for the therapeutic function of fish oil diet that blocks miR-21, thereby increasing PTEN levels to prevent expression of CSF-1 in breast cancer.
Additionally, we summarized breast cancer risk associated with the following genetic factors: breast cancer susceptibility high-penetrance genes (BRCA1, BRCA2, p53, PTEN, ATM, NBS1 or LKB1) and low-penetrance genes such as cytochrome P450 genes (CYP1A1, CYP2D6, CYP19), glutathione S-transferase family (GSTM1, GSTP1), alcohol and one-carbon metabolism genes (ADH1C and MTHFR), DNA repair genes (XRCC1, XRCC3, ERCC4/XPF) and genes encoding cell signaling molecules (PR, ER, TNFalpha or HSP70).
EGFR, pMAPK, pAkt and PTEN status by IHC were not significantly associated with response to trastuzumab, TTP, overall survival (OS1, OS2, OS3) and CNS metastases incidence.
Over the past decade mutations discovered in genes such as BRCA1, BRCA2, TP53 and PTEN, have emerged as high-penetrance susceptibility genes and are clinically relevant for determination of breast cancer risk.
Women diagnosed with breast cancer who carry pathogenic variants in genes with proven associations with breast cancer (BRCA1/2) or highly likely associations (PTEN, PALB2) require additional risk assessment to facilitate treatment decisions that will limit in-breast tumor recurrence and contralateral breast cancer.