Using an Affymetrix 10K SNP array to screen for gene copy number changes in breast cancer, we detected a single-gene amplification of the ESR1 gene, which encodes estrogen receptor alpha, at 6q25. A subsequent tissue microarray analysis of more than 2,000 clinical breast cancer samples showed ESR1 amplification in 20.6% of breast cancers. Ninety-nine percent of tumors with ESR1 amplification showed estrogen receptor protein overexpression, compared with 66.6% cancers without ESR1 amplification (P < 0.0001). In 175 women who had received adjuvant tamoxifen monotherapy, survival was significantly longer for women with cancer with ESR1 amplification than for women with estrogen receptor-expressing cancers without ESR1 amplification (P = 0.023). Notably, we also found ESR1 amplification in benign and precancerous breast diseases, suggesting that ESR1 amplification may be a common mechanism in proliferative breast disease and a very early genetic alteration in a large subset of breast cancers.

Multiple different oncogenes have been described previously to be amplified in breast cancer including HER2, EGFR, MYC, CCND1, and MDM2. Gene amplification results in oncogene overexpression but may also serve as an indicator of genomic instability. As such, presence of one or several gene amplifications may have prognostic significance. To assess the prognostic importance of amplifications and coamplifications of HER2, EGFR, MYC, CCND1, and MDM2 in breast cancer, we analyzed a breast cancer tissue microarray containing samples from 2197 cancers with follow-up information. Fluorescence in situ hybridizations revealed amplifications of CCND1 in 20.1%, HER2 in 17.3%, MDM2 in 5.7%, MYC in 5.3%, and EGFR in 0.8% of the tumors. All gene amplifications were significantly associated with high grade. HER2 (P < 0.001) and MYC amplification (P < 0.001) were also linked to shortened survival. In case of HER2, this was independent of grade, pT, and pN categories. MYC amplification was almost 3 times more frequent in medullary cancer (15.9%), than in the histologic subtype with the second highest frequency (ductal; 5.6%; P ‫؍‬ 0.0046). HER2 and MYC amplification were associated with estrogen receptor/progesterone receptor negativity (P < 0.001) whereas CCND1 amplification was linked to estrogen receptor/progesterone receptor positivity (P < 0.001). Coamplifications were more prevalent than expected based on the individual frequencies. Coamplifications of one or several other oncogenes occurred in 29.6% of CCND1, 43% of HER2, 55.7% of MDM2, 65% of MYC, and 72.8% of EGFR-amplified cancers. HER2/MYC-coamplified cancers had a worse prognosis than tumors with only one of these amplifications. Furthermore, a gradual decrease of survival was observed with increasing number of amplifications. In conclusion, these data support a major prognostic impact of genomic instability as determined by a broad gene amplification survey in breast cancer.

Phosphatidylinositol 3-kinase (PI3K) is a key player in cell-growth signaling in a number of lymphoid malignancies, but its role in diffuse large B-cell lymphoma (DLBCL) has not been fully elucidated. Therefore, we investigated the role of the PI3K/AKT pathway in a panel of 5 DLBCL cell lines and 100 clinical samples. Inhibition of PI3K by a specific inhibitor, LY294002, induced apoptosis in SUDHL4, SUDHL5, and SUDHL10 (LY-sensitive) cells, whereas SUDHL8 and OCI-LY19 (LYresistant) cells were refractory to LY294002-induced apoptosis. AKT was phosphorylated in 5 of 5 DLBCL cell lines and inhibition of PI3K caused dephosphorylation/inactivation of constitutively active AKT, FOXO transcription factor, and GSK3 in LY-sensitive cell lines. In addition, there was a decrease in the expression level of inhibitory apoptotic protein, XIAP, in the DLBCL cell lines sensitive to LY294002 after treatment. However, no effect was observed in XIAP protein levels in the resistant DLBCL cell lines following LY294002 treatment. Finally, using immunohistochemistry, p-AKT was detected in 52% of DLBCL tumors tested. Furthermore, in univariate analysis, high p-AKT expression was associated with short survival. In multivariate analysis, this correlation was no longer significant. Altogether, these results suggest that the PI3K/AKT pathway may be a potential target for therapeutic intervention in DLBCL. IntroductionB-cell lymphoma represents the malignant counterpart of normal B cells arrested at specific maturational stages. Diffuse large B-cell lymphoma (DLBCL) is considered to be the most common type of lymphoma in adults, accounting for 30% to 40% of cases of non-Hodgkin lymphoma. 1 Although patients with DLBCLs are potentially curable with combination chemotherapy, the disease proves fatal in approximately 50% of patients. 2 The cause of most DLBCLs remains unknown; however, dysregulation of apoptosis or defective repair plays a role in lymphogenesis. 3 A number of constitutively activated growth signaling pathways have frequently been observed in DLBCL including protein kinase AKT and nuclear factor B (NF-B) transcription factor. [4][5][6] Protein kinases have been implicated as having crucial roles in regulating cell growth, metabolic responses, cell proliferation, migration, and apoptosis, which altogether contribute to tumorigenesis. Constitutive activation of these protein kinases, mainly by phosphorylation, has been implicated as contributing to malignant phenotypes in a number of human cancers. [7][8][9] AKT is a serine threonine kinase that gets activated on growth factor and cytokine stimulation. When phosphoinositide-3,4,5-triphosphate (PIP 3 ) is generated by phosphatidylinositol 3Ј-kinase (PI3K) in response to an intracellular signal, it binds to the PH domain of AKT and translocates to the plasma membrane resulting in the activation of phosphoinositidedependent protein kinases (PDK1 and PDK2). Activated PDK1 and PDK2 phosphorylate at the Thr308 and Ser473 residues of the AKT kinase domain, resulting in its activation. ...

Context: Genetic aberration in phosphatidylinositol 3-kinase (PI3K)/AKT pathway has been detected in numerous and diverse human cancers. PIK3CA, which encodes for the catalytic subunit of p110␣ of PI3K, is amplified in some cases of papillary thyroid cancer (PTC). Mutations in the PIK3CA have also been identified in thyroid cancers and, although relatively common in anaplastic thyroid carcinoma, are uncommon in PTC.Objective: The objective of the study was to investigate genetic alterations like PIK3CA gene mutation, PIK3CA amplification, RAS, and RAF mutations and to further explore the relationship of these genetic alterations with various clinicopathological characteristics in Middle Eastern PTC. Design:We used the fluorescence in situ hybridization technique for analysis of PIK3CA amplification from 536 PTC cases, and selected amplified samples were further validated by real-time quantitative PCR. Mutation analysis was done by direct DNA sequencing of PIK3CA, N2-RAS, and BRAF genes.Results: PIK3CA amplification was seen in 265 of 499 PTC cases analyzed (53.1%); PIK3CA gene mutations in four of 207 PTC (1.9%); N2-RAS mutations in 16 of 265 PTC (6%); and BRAF mutations in 153 of 296 PTC (51.7%). N-RAS mutations were-associated with an early stage (P ϭ 0.0465) and lower incidence of extrathyroidal extension (P ϭ 0.027), whereas BRAF mutations were-associated with metastasis (P ϭ 0.0274) and poor disease-free survival (P ϭ 0.0121) in PTCs. P apillary thyroid carcinoma (PTC) is the most common malignant thyroid tumor, representing 80 -90% of all thyroid malignancies. PTC is usually well differentiated; however, the clinical behavior of PTC varies widely. For example, incidental microcarcinomas grow very slowly and are noninvasive or minimally invasive. On the other hand, invasive PTC with metastasis can be lethal. PTC often recurs many years after surgical removal. The prognosis for PTC is often favorable; however, approximately 20% of PTC tumors recur, and some reach advanced stages (1). Several clinicopathological variables including stage, cancer invasion, and distant metastasis are used for prognostication and treatment selection for PTC (2, 3). A better understanding of the factors and mechanisms determining the aggressive behavior of some papillary carcinomas is critical in developing new treatment. Conclusion