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).
A new tumor suppressor gene PTEN/MMAC1 was recently isolated at chromosome 10q23 and found to be inactivated by point mutation or homozygous deletion in glioma, prostate and breast cancer.
A total of 360 paired breast carcinoma and adjacent normal tissue samples from 180 sporadic breast cancer patients were included in the present study and examined for PTEN promoter methylation status by methylation-specific polymerase chain reaction.
We found that seven haplotypes from four haplotype blocks located within three genes (NBS1, PTEN, and BRIP1) were significantly associated with breast cancer risk.
Previously undetected germline mutations in BRCA1, BRCA2, CHEK2, TP53, and PTEN that predispose to breast cancer; frequencies of these mutations among families with negative genetic test results.
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.
Low PTEN levels and PIK3CA mutations predict resistance to neoadjuvant lapatinib and trastuzumab without chemotherapy in patients with HER2 over-expressing breast cancer.
The most important cause of developing hereditary breast cancer is germline mutations occurring in breast cancer (BCs) susceptibility genes, for example, BRCA1, BRCA2, TP53, CHEK2, PTEN, ATM, and PPM1D.
The nine coding exons of the PTEN gene were screened for harboring germline mutations using denaturing gradient gel electrophoresis (DGGE) complemented by sequencing, in two subsets of Israeli patients: 12 patients clinically diagnosed with BRRS, and 89 women with an apparent inherited predisposition to breast cancer, some with salient features of CD.
BRCA1 and BRCA2 are the genes most commonly associated with inherited breast cancer; however, mutations in TP53 and PTEN cause Li-Fraumeni syndrome and Cowden syndrome, respectively, both of which are associated with high lifetime risks of breast cancer.
The absence of known histological features for breast cancer arising in a PTEN-mutant background prompted us to explore them for potential new markers.
We searched for germline mutations in PTEN in a 49-year-old female patient who presented trichilemmoma with previous history of breast carcinoma, and thyroidectomy for a thyroid nodule.
Epidemiologic studies suggested that mutations of the PI3K/PTEN/AKT pathway genes are associated with cancer risk, yet no data are available for PTEN rs701848, PIK3CA rs2699887, and AKT1 rs2494752 polymorphism and breast cancer(BC) risk.
Consequently, new genes have emerged as breast cancer susceptibility genes, including rare germline mutations in high penetrant genes, such as TP53 and PTEN, and more frequent mutations in moderate penetrant genes, such as CHEK2, ATM and PALB2.
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.
Germline DNA from 1054 BRCA-mutation-negative Hispanic women with hereditary BC (BC diagnosed at age <51 years, bilateral BC, breast and ovarian cancer, or BC diagnosed at ages 51-70 years with ≥2 first-degree or second-degree relatives who had BC diagnosed at age <70 years), 312 local controls, and 887 multiethnic cohort controls was sequenced and analyzed for 12 known and suspected, high-penetrance and moderate-penetrance cancer susceptibility genes (ataxia telangiectasia mutated [ATM], breast cancer 1 interacting protein C-terminal helicase 1 [BRIP1], cadherin 1 [CDH1], checkpoint kinase 2 [CHEK2], nibrin [NBN], neurofibromatosis type 1 [NF1], partner and localizer of BRCA2 [PALB2], phosphatase and tensin homolog [PTEN], RAD51 paralog 3 [RAD51C], RAD51D, serine/threonine kinase 11 [STK11], and TP53).
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.