Engagement of NKG2D by their ligands (NKG2D-L), as the human major histocompatibility complex class I-related molecules MIC-A and the UL16-binding proteins, on cytolytic lymphocytes leads to the ...enhancement of antitumour effector functions. These ligands are missing or expressed at very low levels on leukaemic cells; furthermore, they can be shed by tumour cells and inhibit cytolytic activity of lymphocytes. Herein, we show that in vivo administration of all-trans-retinoic acid (ATRA) or the histone deacetylase inhibitor sodium valproate (VPA) to patients affected with acute myeloid leukaemia (AML) M3 or M1 respectively, leads to the induction of transcription and expression of NKG2D-L at the surface of leukaemic cells. Apparently, no detectable shedding of the soluble form of these molecules was found in patients' sera. Conversely, AML blasts from patients treated with chemotherapy not including ATRA or VPA did not show any induction of NKG2D-L transcription. Furthermore, upon therapy with ATRA or VPA, leukaemic blasts become able to trigger lytic granule exocytosis by autologous CD8(+) T and natural killer lymphocytes, as shown by CD107a mobilization assay, followed by leukaemic cell lysis. These findings indicate that ATRA and VPA may contribute to the activation of cytolytic effector lymphocytes in vivo, possibly enhancing their anti-leukaemic effect.
Personalized medicine emphasizes the practice of considering individual patient characteristics as opposed to that centered on standards derived from epidemiological studies which, by definition, do ...not take into account the variability of individuals within a given population. When applied to oncology, personalized medicine is an even more complex concept because it extends the variability beyond the individual patient to the individual tumor. Indeed, the great genotypic and phenotypic variability (both in primary and metastatic sites of cancer) the development of targeted therapies, and the growing availability of biological assays complicate the scenario of personalized medicine in the oncological field. In this paper we review the results of anti-epidermal growth factor receptor (EGFR) monoclonal antibody (mAb) therapy in metastatic colorectal cancer (mCRC) in the context of tumor biology, delineating the future prospects of patient-tailored medicine in this area. In particular, we deal with EGFR inhibition by Cetuximab, a chimeric mouse human IgG1 mAb, and panitumumab, a fully human IgG2 mAb. We discuss the clinical impact of anti-EGFR mAbs on wild-type (WT) KRAS mCRC, also taking into account the feasibility of novel multi-marker approaches to treatment decision-making, aimed at increasing the predictive power of pre-therapy biomarkers. Experimental topics and fields of ongoing research, such as targeting microRNAs (miRNAs) with novel anticancer drugs and epigenetics in CRC are also addressed.
Molecular characterization of an Italian series of sporadic GISTs Origone, P.; Gargiulo, S.; Mastracci, L. ...
Gastric cancer : official journal of the International Gastric Cancer Association and the Japanese Gastric Cancer Association,
10/2013, Letnik:
16, Številka:
4
Journal Article
Recenzirano
Purpose
Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors of the gastrointestinal tract. Most (80 %) contain activating mutations in the KIT receptor tyrosine kinase, roughly 10 % in ...platelet-derived growth factor receptor-alpha (PDGFRA). In a small subset, BRAF mutations are an alternative molecular pathway. GISTs respond well to imatinib, but low response is seen in patients with wild-type KIT or PDGFRA. Resistance has also been reported as a result of mutations in downstream effectors such as BRAF.
Methods
We provide here a molecular characterization of a series of primary GISTs from Italian patients. Of 121 GIST cases diagnosed between 2000 and 2012, 83 were evaluated by PCR amplification and direct sequencing for mutations in KIT exons 8, 9, 11, 13, and 17, PDGFRA exons 12, 14, and 18, and BRAF exon 15. Eighty-one GISTs also underwent K-RAS testing.
Results
Sixty-four GISTs were positive: 55 had mutations in KIT and 9 in PDGFRA; 16 patients were mutation negative. Three samples came from NF1 patients and were KIT- and PDGFRA negative. Overall, we identified six novel mutations in KIT (p.K550_M552delinsL, p.Q556_W557delinsG p.Q556_G575del, p.W557_V559delinsQ p.P573_R588dup, p.G592_K593dup) and one novel mutation in PDGFRA (p.D842_N848delinsVDV), thus contributing to widening the spectrum of known mutations in GIST tumors and confirming the most frequently altered regions underlying GIST development.
Conclusions
Among the 64 KIT- and PDGFRA-positive sporadic patients in our series, no BRAF or KRAS mutations were identified, suggesting that co-occurrence of these mutations is likely to be rare in the northwestern Italian population and not a frequent cause of primary resistance to imatinib in KIT-positive GIST patients.
Lapatinib, a dual HER2 and EGFR tyrosine kinase inhibitor is highly active in HER2+ breast cancer. However, its efficacy is limited by either primary or acquired resistance. Although mutations in ras ...genes are rarely found in breast cancer, H-ras overexpression is frequently observed. Moreover, genetic alterations that do not directly involve ras such as Brk amplification, ultimately result in increased ras signaling. Using SKBR3 cells, a HER2+ breast cancer cell line that is naturally devoid of mutations in PI3KCA, PTEN, BRAF, and ras we show that both H-ras overexpression and expression of an oncogenic ras allele (ras V12) reduce susceptibility to lapatinib in analogy to what observed with activating PI3KCA mutations and with a constitutively active form of Akt. Importantly, we found that resistance to lapatinib due to ras overexpression or to ras V12 is overcome by MEK inhibition with U0126, suggesting a key role for the MEK-Erk pathway in ras-induced resistance. Similar results were obtained in BT474 cells, another HER+ breast cancer cell line. Therefore, our data indicate that overexpressed/mutated ras may act as a biological modifier of the response to lapatinib. Combining MEK inhibitors with lapatinib may help overcome this form of resistance and increase the efficacy of lapatinib in these tumors.
Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have become a treatment after first-line chemotherapy in patients with advanced NSCLC. We assessed the predictive and ...prognostic role of EGFR and Kras mutations in NSCLC patients treated with TKIs after progression, not included in clinical trials. Gefitinib 250 mg or Erlotinib 150 mg per os were administered to 70 patients. Radiological assessment was performed every six weeks. EGFR and Kras mutations were found in 21.4% and 24.3% of patients, respectively. At multivariate analysis, Kras mutation was positively associated with progression-free survival (PFS; HR=0.71, 95% CI: 0.53-0.96; p=0.027) and, less clearly, with response (OR=1.84, 95% CI: 0.98-3.45; p=0.057) and survival (HR=0.74, 95% CI:0.54-1.02; p=0.066). EGFR mutation influenced positively PFS (HR=0.69, 95% CI: 0.47-1.02; p=0.06), but not survival. In conclusion, in our unselected patients mutation of Kras correlated with a better outcome. The small number of patients may explain some discrepancies with data in literature.
We show that a tower of torsors under affine group schemes can be dominated by a torsor. Moreover, if the base is the spectrum of a field and the structure group schemes are finite, the tower can be ...dominated by a finite torsor. \par As an application, we show that if X is a torsor under a finite group scheme G over a scheme S which has a fundamental group scheme, then X has a fundamental group scheme too and that this group \boldsymbol {\pi }(X) identifies with the kernel of the map \boldsymbol {\pi }(S)\to G.
In cancer patients, the ability to detect disseminated tumour cells in peripheral blood or bone marrow could improve prognosis and consent both early detection of metastatic disease and monitoring of ...the efficacy of systemic therapy. These objectives remain elusive mainly due to the lack of specific genetic markers for solid tumours. The use of surrogate tissue-specific markers can reduce the specificity of the assays and give rise to a clinically unacceptable false-positive rate. Mammaglobin (MAM) and maspin are two putative breast tissue-specific markers frequently used for detection of occult tumour cells in the peripheral blood, bone marrow and lymph nodes of breast cancer patients. In this study, it was evaluated whether MAM and maspin gene expression may be induced in the normal blood and bone marrow cells exposed to a panel of cytokines, including chemotactic factors (C5a, interleukin (IL)-8), LPS, proinflammatory cytokines (TNF-alpha, IL-1beta) and growth factors (IL-3, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor). The experimental data show that all cytokines included in the panel, except for IL-8, were able to induce maspin expression; on the contrary, MAM gene was never induced. These results suggest that MAM is more specific than maspin and that the possible interference of cytokines should be taken into account in interpreting molecular assays for detection of isolated tumour cells.
ON THE "GALOIS CLOSURE" FOR TORSORS GARUTI, MARCO A.
Proceedings of the American Mathematical Society,
11/2009, Letnik:
137, Številka:
11
Journal Article
Recenzirano
Odprti dostop
We show that a tower of torsors under affine group schemes can be dominated by a torsor. Moreover, if the base is the spectrum of a field and the structure group schemes are finite, the tower can be ...dominated by a finite torsor. As an application, we show that if X is a torsor under a finite group scheme G over a scheme S which has a fundamental group scheme, then X has a fundamental group scheme too and that this group π(X) identifies with the kernel of the map π(S) → G.
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