Immunohistological recognition of cyclin D1 expression by non-lymphoid cells among lymphoid neoplastic cells

Area of Science:

• Hematopathology
• Cellular Biology
• Immunohistochemistry

Background:

• Cyclin D1 immunostaining is crucial for diagnosing lymphoproliferative lesions.
• Non-neoplastic cell expression of Cyclin D1 can lead to diagnostic ambiguity.
• Understanding normal Cyclin D1 expression is vital for accurate pathology interpretation.

Purpose of the Study:

• To investigate the prevalence and types of non-neoplastic cells expressing Cyclin D1 in haematopathological samples.
• To identify specific normal cell populations that exhibit Cyclin D1 positivity.
• To provide guidance for avoiding misinterpretation of Cyclin D1-positive tumors.

Main Methods:

• Review of 231 haematopathological samples stained for Cyclin D1.
• Analysis of formalin-fixed and B-5 fixed (bone marrow trephines) samples.
• Examination of EDTA-decalcified specimens.

Main Results:

• 94% of cases showed Cyclin D1 expression in at least one non-neoplastic cell type.
• Endothelial cells and histiocytes were the most frequent Cyclin D1-positive non-neoplastic cells (92%).
• Other positive non-neoplastic cells included fat cells, fibroblasts, glial cells, spermatocytes, smooth muscle cells, osteoblasts, and epithelial cells.

Conclusions:

• Numerous normal cell types express Cyclin D1.
• Awareness of Cyclin D1 expression in non-neoplastic cells is essential for accurate diagnosis of hematological malignancies.
• This knowledge helps prevent misdiagnosis of Cyclin D1-driven tumors.