Suitability of Different Cytological Preparations for Molecular Analysis of Advanced Non-Small Cell Lung Cancers

Around 85% of non-small cell lung cancers (NSCLCs) are diagnosed at an advanced stage (IIIB to IV), where therapeutic options depend on molecular analysis. However, diagnostic material for molecular testing is often represented by cytological samples which are generally scarce and span a wide range of preparation types. Thus, the primary objective is to efficiently manage materials for molecular profiling. This study aims to evaluate the suitability of different cytological samples to assess morphological and molecular characteristics of advanced NSCLC.

Sixty-seven cytological samples obtained from patients with advanced NSCLC were utilized. The series encompassed different procedure types (fine-needle aspiration cytology, transbronchial needle aspiration, effusions) processed by cell blocks in 54% (n = 36), direct smears in 33% (n = 22), and liquid-based cytology (LBC) in 13% (n = 9). Cytological diagnoses were routinely performed, and molecular analysis was conducted using next-generation sequencing (NGS) and real-time polymerase chain reaction (RT-PCR) methods.

Adequate quantity and quality of nucleic acids were obtained from all the samples, allowing molecular profiling. Combined NGS and RT-PCR analysis showed wild-type profiles in 62.7% (n = 42) and mutated profiles in 37.3% (n = 25) of the samples. Kirsten Rat Sarcoma Virus (KRAS) mutations were identified in 19.5% (n = 13) of samples, EGFR mutations in 10.4% (n = 7) and v-raf murine sarcoma viral oncogene homolog B (BRAF) mutations in 2.9% (n = 2). Identified chromosomal alterations were v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2 (ERBB2) duplication in 2.9% (n = 2).

The cytological sample types examined in this study proved to be suitable for molecular testing, in addition to conventional morphologic diagnosis, showing versatility and adaptability to different clinical contexts. Molecular testing on cytological samples is accurate and fast, representing a valid tool for molecular profiling of advanced NSCLC.