[Initial experiences with a monoclonal antibody to the progesterone receptor complex]

Area of Science:

• Oncology
• Immunohistochemistry
• Molecular Biology

Context:

• Estrogen receptor (ER) detection is established in breast cancer diagnostics.
• A novel monoclonal antibody (mab), Mi 60-10, targeting the progesterone receptor (PR) complex has become available.
• This antibody shows cross-reactivity with human PR, validated by Western-Blot analysis.

Purpose:

• To evaluate the practical performance of the Mi 60-10 mab for progesterone receptor detection in primary breast carcinomas.
• To compare the efficacy of the Mi 60-10 mab with the established ER-ICA-Kit.
• To assess the utility of the mab in various sample types, including frozen and formalin-fixed paraffin-embedded tissues, and cytological samples.

Summary:

• The Mi 60-10 mab demonstrated comparable success to the ER-ICA-Kit in frozen sections.
• Crucially, the Mi 60-10 mab successfully detected progesterone receptors in formalin-fixed, paraffin-embedded breast cancer samples, even those stored long-term.
• Immunocytochemical detection of progesterone in cytological samples was as effective as estrogen detection and comparable to histological sections.

Impact:

• Enables comprehensive immunocytochemical diagnosis of mammary carcinoma, including PR status in routinely processed paraffin sections.
• Offers a reliable method for PR detection, potentially reducing reliance on the DCC-method.
• Highlights the potential of highly specific monoclonal antibodies for accurate cancer diagnostics.