Reference Medicine's Medical Director, Zoran Gatalica, MD, presents ECP 2023
Sep 12, 2023
New research was presented at the 35th European Congress of Pathology on tumor-infiltrating lymphocytes and HER2 status in invasive apocrine breast carcinoma.
As presented at the 35th European Congress of Pathology, 2023.
The assessment of tumor-infiltrating lymphocytes in invasive apocrine carcinoma of the breast in relation to the Her2 status
Zoran Gatalica1, Nataliya Kuzumova1, Inga Rose1 and Semir Vranic2
1Reference Medicine, 2College of Medicine, Qatar University
Background & objectives
Tumor-infiltrating lymphocytes (TIL) represent a robust immunologic biomarker mediating chemotherapy and immunotherapy responses. In the current study, we assessed the tumor-infiltrating lymphocytes (TIL) in invasive apocrine carcinomas of the breast (Apoca) in relation to the Her2 status.
Methods
The current study used a cohort of 54 well-characterized, naïve Apoca. All patients were women, with a mean age of 64 years (range 39–83 years). The TIL distribution was assessed using the hematoxylin and eosin whole slide/scanned images following the recommendations of the international TILs working group 2014 [Ann Oncol 26(2), 2015].
Results
Forty carcinomas were “pure apocrine” [PAC; ER-/AR+)], and the remaining 13 were classified as “apocrine-like” [ALC; ER+/-, AR+/-]. HER-2/neu was positive (score 3+ by IHC and/or amplified by FISH) in 18/40 (45%) PAC and 3/13 ALC (23%). The prevalence of HER2-low expression (scores 1+ and 2+ without HER2 amplification) in Apoca was high (21/53, 40%); the HER2-low phenotype was more prevalent in “triple-negative” PAC than in ALC (68% vs. 46% p<0.001). Levels of TIL were low (≤10%) in 75% Apoca (median: 5%, range 0–50%). TIL levels were significantly higher in ALC than in PAC (p = 0.05). Her2 status had no impact on the TIL distribution (p=0.45).
Conclusion
Invasive apocrine carcinomas of the breast have predominantly low TIL, particularly PAC. The prevalence of the HER2-low phenotype in apocrine carcinomas is high, which should have therapeutic and clinical implications given the recently approved therapies with antibody-drug conjugates for Her2-low breast cancers.
