Current applications of molecular testing on body cavity fluids

Abstract

IntroductionEffusion cytology has a high sensitivity for the diagnosis of malignancy and provides abundant material for molecular testing. Effusion draining is a minimally invasive procedure with few complications.Materials and methodsWe performed a review of publications regarding the use of molecular testing in serous effusions.ResultsIn diagnostics, BAP‐1 IHC and CDKN2A FISH are powerful tools for the diagnosis of malignant mesothelioma. FISH, PCR, and EBER‐ISH work well in lymphomas. RT‐PCR may enhance the diagnosis of secondary epithelial malignancies. In theranostics, molecular testing on serous effusions is widely reported for the detection of alterations in genes related to lung carcinomas, such as EGFR, ALK, ROS1, and BRAF. PD‐L1 expression testing by immunohistochemistry (IHC) also seems to be viable in this type of sample. HER2 FISH and IHC provide actionable results in the context of breast malignancies. Results in serous effusions seem to be equivalent to tissue biopsies for most applications and across different molecular techniques. The most interesting technology is next‐generation sequencing (NGS), given its ability to sequence multiple genes on a single sample and the decreasing costs that have closely followed increasing throughputs. Cell‐free DNA from effusion supernatants might be the most promising area for future research, showing superiority to serum and even to cell‐block samples in limited studies.ConclusionsMolecular tests are viable in serous effusion specimens when sufficient material is available. Given the rising importance of molecular testing we expect this to be an active field of research in the near future.

Next‐generation sequencing in residual liquid‐based cytology specimens for cancer genome analysis

“…Cytology specimens are used for immunocytochemical, biochemical, and molecular analyses, and are deemed as beneficial diagnostic tools for cytopathologists and pathologists in cancer screening and molecular diagnosis. [1][2][3] Liquid-based cytology (LBC) has recently been used in clinical settings as well as for immunocytochemical and molecular analyses. LBC specimens are potentially promising for cancer molecular testing, particularly for next-generation sequencing (NGS).…”

“…Cytology is a less invasive clinical procedure than histological examination useful for cancer screening and histological grading of tumor subtypes. Cytology specimens are used for immunocytochemical, biochemical, and molecular analyses, and are deemed as beneficial diagnostic tools for cytopathologists and pathologists in cancer screening and molecular diagnosis 1‐3 . Liquid‐based cytology (LBC) has recently been used in clinical settings as well as for immunocytochemical and molecular analyses.…”

Molecular Profiling of Malignant Pleural Effusions with Next Generation Sequencing (NGS): Evidence that Supports Its Role in Cancer Management

“…The cell pellet is subsequently used to form diverse preparations including direct smears, cytospins, liquid-based cytology (LBC) slides and/or formalin-fixed paraffin-embedded (FFPE) cell blocks; these are stained and evaluated morphologically to formulate a diagnosis [ 2 , 9 ]. Ancillary techniques such as Immunohistochemistry (IHC) and Fluorescence in situ Hybridization (FISH) are routinely applied on any of the aforementioned preparations to solve selective diagnostic issues—e.g., metastatic adenocarcinoma vs. mesothelioma differential diagnosis; confirmation of the primary malignancy site or provide clinically relevant prognostic and predictive information; examples of the latter include HER2 testing in breast cancer and PD-L1 testing to initiate immunotherapy [ 2 , 9 , 10 ]. Notably, similar to tissue biopsies, isolation and further processing of DNA, mRNA, miRNAs, and proteins are highly effective on MPEs [ 2 , 8 , 10 ].…”

“…Ancillary techniques such as Immunohistochemistry (IHC) and Fluorescence in situ Hybridization (FISH) are routinely applied on any of the aforementioned preparations to solve selective diagnostic issues—e.g., metastatic adenocarcinoma vs. mesothelioma differential diagnosis; confirmation of the primary malignancy site or provide clinically relevant prognostic and predictive information; examples of the latter include HER2 testing in breast cancer and PD-L1 testing to initiate immunotherapy [ 2 , 9 , 10 ]. Notably, similar to tissue biopsies, isolation and further processing of DNA, mRNA, miRNAs, and proteins are highly effective on MPEs [ 2 , 8 , 10 ]. The latter comprise an optimal material for analysis techniques such as PCR and sequencing, while molecular testing can successfully be performed on all previously mentioned cell pellet-based preparations besides effusion supernatants [ 2 , 8 , 9 , 10 , 11 ].…”

“…Notably, similar to tissue biopsies, isolation and further processing of DNA, mRNA, miRNAs, and proteins are highly effective on MPEs [ 2 , 8 , 10 ]. The latter comprise an optimal material for analysis techniques such as PCR and sequencing, while molecular testing can successfully be performed on all previously mentioned cell pellet-based preparations besides effusion supernatants [ 2 , 8 , 9 , 10 , 11 ].…”