Lung Molecular Cytopathology: EGFR and Beyond

The Importance of Biomarker Testing in the Treatment of Advanced Non-Small Cell Lung Cancer: A Podcast

The identification of actionable biomarkers and development of targeted therapies have revolutionized the field of lung cancer treatment. In patients with advanced non-small cell lung cancer (NSCLC), biomarker testing can inform selection of effective targeted therapies as well as avoid therapies that are less likely to be effective in certain populations. A growing number of actionable targets, including those involving EGFR, ALK, ROS1, BRAF, MET, KRAS, NTRK, RET, HER2, and PD-L1, can be identified with biomarker testing. More than half of patients with advanced NSCLC have tumors that harbor genetic alterations that can be targeted. When these patients are treated with targeted therapy, survival and quality of life may be significantly improved. In addition, broad-based molecular testing may detect alterations identifying patients who are potentially eligible for current or future clinical trials. Comprehensive biomarker testing rates in communities are often low, and turnaround times for results can be unacceptably long. There is an unmet need for widespread, efficient, and routine testing of all biomarkers recommended by clinical guidelines. New testing techniques and technologies can make this an attainable goal. Panel-based sequencing platforms are becoming more accessible, and molecular biomarker analysis of circulating tumor DNA is becoming more common. In this podcast, we discuss the importance of biomarker testing in advanced NSCLC and explore topics such as testing methodologies, effect of biomarker testing on patient outcomes, emerging technologies, and strategies for improving testing rates in the United States. Supplementary file1 (MP4 121301 KB).

Expression of fibroblast activation protein in lung cancer and its correlation with tumor glucose metabolism and histopathology

PURPOSE

To explore the expression of fibroblast activation protein (FAP) in lung cancer (LC) and its correlation with tumor glucose metabolism and histopathology.

METHODS

From June 2018 to November 2020, 73 patients with newly diagnosed LC were included. Immunohistochemical staining was used to quantify FAP expression in tumors. The histopathological type and tumor grade were determined via histopathological examination. The tumor glucose metabolism parameters and tumor maximal diameter were measured via [¹⁸F] F-FDG PET/CT. Univariate and multivariate analysis were performed to study the correlation of FAP expression levels with glucose metabolism variables and tumor histopathology.

RESULTS

Positive FAP expression was observed in 97.3% (71/73) LC lesions, which was significantly higher than 87.7% (64/73) of [¹⁸F] F-FDG positivity observed on PET/CT (χ² = 4.818, P = 0.028). In 12 early adenocarcinomas (ADCs), only three lesions (25%) were positive for [¹⁸F] F-FDG on PET/CT; however, 10 lesions (83.3%) were positive for FAP. When FAP expression was classified into low level (scores ≤ 3) and high level (scores > 4), high FAP level was found in 80.8% tumors and low FAP level in the other 19.2% tumors. High FAP level was identified in 100.0% of squamous cell carcinomas (SCCs), 85.7% of ADCs, 66.7% (4/6) of large cell neuroendocrine carcinomas (LCNCs), and 40.0% (4/10) of small cell lung cancers (SCLCs) (P < 0.05). In non-mucinous ADC lesions, on univariate analysis, FAP expression level showed a close relationship with tumor metabolism parameters (maximal standard uptake value (SUVmax), mean standard uptake value (SUVmean), and total lesion glycolysis (TLG)), tumor diameter, tumor grade, and lesion attenuation (P < 0.05).

CONCLUSION

The present study demonstrates that FAP is widely expressed in LC and shows great variation in different histopathological types. A high positive rate of FAP expression implies that FAP-targeted imaging may be a sensitive modality for diagnosing LC, especially in early ADCs. Further validation with such probes is warranted.