The diagnostic utility of CK5/6 and p63 in fine-needle aspiration of the breast lesions diagnosed as proliferative fibrocystic lesion

Cell Block-Based Two-Dimensional and Immunocytochemical Analyses Could Reduce Atypical/Indeterminate Case Frequency in Breast Fine-Needle Aspiration Cytology: A Retrospective Analysis

INTRODUCTION

In fine-needle aspiration of the breast (FNAB), the "atypical" category encompasses both benign and malignant lesions, particularly papillary proliferative lesions, as per the latest WHO classification. We aimed to reduce atypical cases and improve diagnostic accuracy by investigating the utility of cell block (CB) analysis.

METHODS

FNAB CB samples (2018-2022) were reviewed using smear only or CBs. CB-based diagnosis was performed with 2D morphological analysis and immunocytochemistry using ER, CK5/6, p63, SMA, and CD56. Samples were reclassified as "benign," "atypical," "suspicious of malignancy," "malignant," or "insufficient/inadequate." Atypical cases were reexamined. Diagnoses were validated histologically.

RESULTS

On examining the FNAB samples (n = 149; 32 atypical), 2D CB sectioning achieved a clearer definition of myoepithelial cells and fibrovascular cores than Papanicolaou staining. Immunocytochemistry was evaluated for 36 cases: estrogen receptor (ER)- and CK5/6+ tumors were reclassified as benign; ER+ and CK5/6- tumors as malignant; p63- tumors as invasive; papillary malignant tumors with a smooth muscle actin (SMA)+ fibrovascular core and p63- myoepithelial cells as encapsulated papillary carcinoma; and CD56+ carcinomas as neuroendocrine carcinoma. Diagnostic rates were as follows: benign (44% FNAB, 51% CB), atypical (21% FNAB, 3% CB), suspicious of malignancy and malignant (28% FNAB, 40% CB), and insufficient/inadequate (7% FNAB, 6% CB). CB achieved >85% sensitivity, specificity, and positive and negative predictive values.

CONCLUSION

CBs represent 3D FNA cell morphology using 2D sections, enabling adaption of pathology criteria to the cytological material. Immunocytochemical staining of CBs can predict low nuclear grade papillary tumors and reduce atypical case frequency, improving diagnostic accuracy.

Role of β-Interferon Inducer (DEAE-Dextran) in Tumorigenesis by VEGF and NOTCH1 Inhibition along with Apoptosis Induction

As a novel target for breast cancer, interferon inducers have found its role as anti-angiogenic agents with diethylaminoethyl dextran (DEAE-Dextran) being a molecule used for centuries as a transfection agent. Our results herein offer an explanation for the emergence of DEAE-Dextran as an anti-tumor agent for TNBC with in-depth mechanistic approach as an anti-angiogenic molecule. DEAE-Dextran has found to possess cytotoxic activity demonstrated during the various in vitro cytotoxicity assays; moreover, as an anti-oxidant, DEAE-Dextran has shown to possess excellent reactive oxygen species scavenging activity. The interferon inducing capacity of DEAE-Dextran was determined qualitatively as well as quantitatively specifically demonstrating overexpression of β-interferon. As a measure of anti-proliferative activity, DEAE-Dextran exhibited reduced ki67, p53, and PCNA levels. Also, overexpression of CK5/6 and p63 in DEAE-Dextran treated animals indicated improvement in breast cell morphology along with an improvement in cell–cell adhesion by virtue of upregulation of β-catenin and E-cadherin. Anti-angiogenic property of DEAE-Dextran was concluded by the downregulation of CD31, VEGF, and NOTCH1 both in vivo and in vitro. Further, apoptosis due to DEAE-Dextran, initially determined by downregulation of Bcl2, was confirmed with flow cytometry. Overall, results are defensive of DEAE-Dextran as an emerging anti-tumor agent with mechanisms pertaining to β-interferon induction with probable VEGF and NOTCH1 inhibition as well as apoptosis which still needs to be studied in further depth.