EGFR is frequently mutated and amplified in lung adenocarcinomas sensitive to EGFR inhibitors gefitinib and erlotinib. A secondary mutation, T790M, has been associated with acquired resistance but has not been shown to be sufficient to render EGFR mutant/amplified lung cancers resistant to EGFR inhibitors. We created a model for studying acquired resistance to gefitinib by prolonged exposure of a gefitinib-sensitive lung carcinoma cell line (H3255; EGFR mutated and amplified) to gefitinib in vitro. The resulting resistant cell line acquired a T790M mutation in a small fraction of the amplified alleles that was undetected by direct sequencing and identified only by a highly sensitive HPLC-based technique. In gefitinib-sensitive lung cancer cells with EGFR mutations and amplifications, exogenous introduction of EGFR T790M effectively conferred resistance to gefitinib and continued ErbB-3/PI3K/Akt signaling when in cis to an activating mutation. Moreover, continued activation of PI3K signaling by the PIK3CA oncogenic mutant, p110alpha E545K, was sufficient to abrogate gefitinib-induced apoptosis. These findings suggest that allelic dilution of biologically significant resistance mutations may go undetected by direct sequencing in cancers with amplified oncogenes and that restoration of PI3K activation via either a T790M mutation or other mechanisms can provide resistance to gefitinib.

The sensitivity of conventional DNA sequencing in tumor biopsies is limited by stromal contamination and by genetic heterogeneity within the cancer. Here, we show that microreactor-based pyrosequencing can detect rare cancer-associated sequence variations by independent and parallel sampling of multiple representatives of a given DNA fragment. This technology can thereby facilitate accurate molecular diagnosis of heterogeneous cancer specimens and enable patient selection for targeted cancer therapies.

HIV and human papillomavirus (HPV) coinfected patients are at high risk of developing precancerous anal lesions (anal intraepithelial neoplasia) and anal malignancies. 1 The natural history (that is, progression and persistence) of HPV-associated lesions is accelerated by HIV-related immunosuppression, which may result in the reactivation of previously acquired HPV infection and loss of control of HPV viral replication. 2 The longer life expectancy of these coinfected patients in the era of HAART provides an opportunity for invasive anal carcinoma to develop from its dysplastic precursor. The prognosis of anal squamous cell carcinoma is poor in HIV-positive patients, who often present with advanced tumors. 3 The appropriate treatment of patients with advanced anal cancer and HIV infection is uncertain. 4 Concomitant radiation therapy and chemotherapy (fluorouracil and mitomycin-C) is the current standard of care for HIV-negative patients with invasive anal carcinoma, and that approach has been investigated and applied successfully in HIV-positive patients with similar anal cancers, particularly those with CD4ϩ T-lymphocyte counts greater than 200 cells/L. 5,6 HIV-positive patients with anal cancer treated with HAART tend to fare better than those patients who are not receiving HAART. 7 It is prudent to point out that our patient never had an anal Papanicolaou (Pap) test (Fig 3, high-grade dysplastic squamous cells; ThinPrep, Cytyc Corporation, Marlborough, MA). HIV-associated anal carcinoma appears to mirror cervical carcinoma in unscreened women, presenting late in the course of the disease and having a protracted, ultimately fatal, course. 8 Screening of HIV-positive patients for anorectal dysplasia and/or malignancy by means of an anal Pap test could save lives. 9

Purpose This is a phase II, multicenter, open-label study of chemotherapy-naïve patients with non–small-cell lung cancer (NSCLC) and age ≥ 70 years who were treated with erlotinib and evaluated to determine the median, 1-year, and 2-year survival. The secondary end points include radiographic response rate, time to progression (TTP), toxicity, and symptom improvement. Patients and Methods Eligible patients with NSCLC were treated with erlotinib 150 mg/d until disease progression or significant toxicity. Tumor response was assessed every 8 weeks by computed tomography scan using Response Evaluation Criteria in Solid Tumors. Tumor samples were analyzed for the presence of somatic mutations in EGFR and KRAS. Results Eighty eligible patients initiated erlotinib therapy between March 2003 and May 2005. There were eight partial responses (10%), and an additional 33 patients (41%) had stable disease for 2 months or longer. The median TTP was 3.5 months (95% CI, 2.0 to 5.5 months). The median survival time was 10.9 months (95% CI, 7.8 to 14.6 months). The 1- and 2- year survival rates were 46% and 19%, respectively. The most common toxicities were acneiform rash (79%) and diarrhea (69%). Four patients developed interstitial lung disease of grade 3 or higher, with one treatment-related death. EGFR mutations were detected in nine of 43 patients studied. The presence of an EGFR mutation was strongly correlated with disease control, prolonged TTP, and survival. Conclusion Erlotinib monotherapy is active and relatively well tolerated in chemotherapy-naïve elderly patients with advanced NSCLC. Erlotinib merits consideration for further investigation as a first-line therapeutic option in elderly patients.