Morphologic analysis of cytology samples obtained by transthoracic needle aspiration (TTNA) is one of the primary methods for diagnosing bronchogenic carcinoma. However, across multiple studies the false negative rate for cytomorphological analysis ranges from 0.2-0.3, and among those diagnosed with lung cancer, the false positive rate for diagnosing the sub-class of small cell carcinoma averages 0.09. These false results lead to additional invasive diagnostic studies and delay treatment. In an effort to augment accuracy and utility of cytopathologic evaluation of TTNA lung samples, we measured the previously reported c-myc x E2F-1/p21WAF1/CIP1 (p21 hereafter) gene expression index in cDNA samples from 78 non-malignant lung tissues and 57 lung cancer tissues. Using the optimal cut-off value, this test correctly classified 72/78 non-malignant and 50/57 malignant samples for a correct classification rate of 90% (95% CI 83.6% - 94.3%), sensitivity of 88%, and specificity of 92%. A CDKN2C/FOSL1 test for distinguishing non-small cell lung cancer (NSCLC) from small cell lung cancer (SCLC) had a PPV of 100% with 63% sensitivity. In order to optimize the robustness and utility of these tests, we developed qPCR methods that enable simultaneous measurement of each target gene and reference gene transcript relative to a known number of internal standard competitive template (CT) molecules using two-color flurometric analysis on real-time platform. For each gene, the native template was quantified with a sequence-specific FAM-labeled probe and the CT was quantified with a sequence-specific Quasar670 labeled probe. Results for each gene thus far demonstrate excellent linearity (R2 > 0.99, slope 1.0 +/- 0.05), relative accuracy (variance < 0.2), signal-to-analyte response (1.0 +/- 0.05) and precision (CV < 30%) over six orders of magnitude, and reliable detection of as few as 10 molecules. Assessing both the c-myc x E2F-1/p21 index and the CDKN2C/FOSL1 test promises to augment cytomorphologic diagnosis of bronchogenic carcinoma in TTNA samples biopsy samples.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5541. doi:1538-7445.AM2012-5541