Monoclonal antibody 44‐3A6 as an adjunct in cytodiagnosis of adenocarcinomas in body fluids

Abstract

Monoclonal antibody (MCA) 44-3A6 detects a cell-surface transmembrane phosphoprotein frequently expressed by pulmonary adenocarcinoma (AC) and associated with glandular differentiation. This antibody has been found to have utility in assessing routine formalin fixed paraffin-embedded pulmonary neoplasms, as well as the cytopathological evaluation of sputum and bronchial brushings. Recently, it has been shown to be useful in cytological diagnosis of pleural effusions. This study is directed at evaluating its effectiveness in detecting immunoreactive neoplastic cells in body fluids (BF) arising in other tissues. A retrospective cohort of 57 cases was studied, consisting of 36 pleural, 19 ascitic, and 2 pericardial BF. After evaluation of Papanicolaou-stained slides, the BF specimens were immunostained with MCA 44-3A6 using the avidin-biotin-peroxidase complex (ABC) method. In 29 cases, tissue sections of the primary tumors, were also available for immunostaining with MCA 44-3A6. Results showed that 39/42 (93%) of AC BF cases were positive and 28/42 (66%) stained intensely (3-4+) with 75-100% of the AC cells staining in each case. All of the 18 benign and non-AC malignant BF were negative. The staining patterns in the tissue sections of the 29 cases that had corresponding BF samples were similar. We conclude from this study that the MCA 44-3A6 (1) is useful in detecting cells consistent with AC in BF; (2) does not stain inflammatory cells or reactive mesothelial cells, thus helping distinguish reactive from malignant BF; and (3) frequency and pattern of expression in BF parallels its expression in tissue specimens. This study confirms that this MCA is a useful adjunct tool in the cytopathological evaluation of BF.

Antigens under cover—The preservation and demasking of selected antigens for successful poststaining immunocytochemistry of effusion, brain smears, and lymph node aspirates

“…Historically, PSICC methodology was tailored to individual cases. Therefore, systematic studies on the reproducibility, efficacy, and reliability of immunostaining are rare . Hence, the present study aimed to fill this gap by establishing reproducible guidelines for PSICC labeling of selected cellular and viral antigens in tissue imprints, FNA, and cytocentrifuged fluids with the focus specifically on antigen preservation and retrieval.…”

Labyrinthin: A distinct pan-adenocarcinoma diagnostic and immunotherapeutic tumor specific antigen

“…It is therefore an accessible therapeutic target for adenocarcinomas that represent approximately 40% of all cancers (cancercentre.com; cancer.org) [26] and includes the deadliest cancers of lung, colorectal, pancreatic, breast, prostate, and liver/intrahepatic bile duct, respectively (cdc.gov). Subsequent to the discovery of labyrinthin [27], which at the time was only referred to as the mouse monoclonal antibody MCA 44-3A6 antigen, numerous papers were published to elucidate the selective, yet broad association of the antigen with adenocarcinomas [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43].…”

<p>Labyrinthin, The Tumor Marker Recognized By MCA 44-3A6: A Case For Pan-Tumor Markers As Targets To Treat Cancer</p>

“…As additional studies confirmed the presence of labyrinthin in lung adenocarcinomas,5,6 the question arose whether labyrinthin, the antigen recognized by MCA 44-3A6, could be equally consistent in sorting adenocarcinomas from other tumor types arising in other tissues. Indeed, MCA 44-3A6 recognized labyrinthin on breast,7 bronchial tract, stomach, small intestine, pancreas and colon in cancer tissues derived from adults;8,9 the aerodigestive tract, exocrine pancreas, neural tissues, renal tubules, and transitional urothelium during human fetal development;10 and more recently labyrinthin has been found to be selectively associated with adenocarcinomas from a variety of cancer cells and tissues (eg, NCI-60 human tumor cell line panel; data not shown). Thus, it turns out that labyrinthin serves as a pan-adenocarcinoma marker regardless of the organ system.…”