The use of HER2 modulation in the adjuvant setting

Prospects for personalized medicine with inhibitors targeting the RAS and PI3K pathways

Tumor genetic analyses have revealed that the signaling pathways regulated by PI3K and RAS are of fundamental importance in a wide variety of human neoplasms, leading to intensive efforts to develop therapeutics that block signaling through these two key pathways. Both pathways frequently undergo a variety of activating alterations, including oncogenic mutations, amplification events and loss of tumor-suppressor genes that are thought to confer aggressive growth properties and enhance survival on neoplastic cells. An attractive hypothesis is that these alterations provide an indication that a particular tumor is addicted to signaling through the affected pathway, thus may provide ideal candidate predictive biomarkers to target these inhibitors to appropriate patient populations. This review highlights recent preclinical progress made on understanding the predictive value of key pathway alterations in response to targeted therapeutics directed against PI3K, AKT, mTOR, BRAF and MEK, and the prospects for biomarker-driven clinical strategies for such inhibitors.

HER-2 status in gastrointestinal stromal tumor

Human epidermal growth factor receptor-2 (HER-2) encodes for the transmembrane glycoprotein HER-2 that is involved in activation of intracellular signal transduction pathways that control cell growth and differentiation. HER-2 is overexpressed in approximately 20% of patients with breast cancer and has been associated with poorer prognosis. Since 1998, the anti-HER-2 antibody trastuzumab has been used for the treatment of patients with HER-2-positive breast cancers. However, little information is available about the relationship between HER-2 and gastrointestinal stromal tumors. This study's purpose was to determine the HER-2 status in gastrointestinal stromal tumors. We found that all 477 cases included in this study were negative (score 0) by immunohistochemistry using HercepTest, and no HER-2 gene amplification was detected in 71 cases submitted to fluorescence in situ hybridization. These results show that HER-2 may not have any role in gastrointestinal stromal tumor pathogenesis and that the neoplasm may not be suitable for treatment with trastuzumab.