In the current study, we assessed the prevalence and molecular features of HER2-low phenotype in the apocrine carcinomas of the breast (ApoCa) and its relationship with tumor-infiltrating lymphocytes (TILs). A cohort of 64 well-characterized therapy-naïve ApoCa was used. The TIL distribution was assessed using the hematoxylin and eosin whole slide/scanned images following the international TILs working group recommendations. Next-generation sequencing (NGS) was performed in a subset of HER2-low ApoCa. All patients were women, with a mean age of 62 years. Forty-three carcinomas were pure apocrine carcinoma (PAC; ER−/AR+), and the remaining 21 were classified as apocrine-like carcinomas (ALCs; ER+/−, AR+/−). HER2/neu was positive (score 3+ by IHC and/or amplified by FISH) in 20/43 (47%) PAC and 4/21 (19%) ALC. The prevalence of HER2-low expression (scores 1+ or 2+ without HER2 amplification) in ApoCa was 39% without significant differences between PAC and ALC (P ═ 0.14); however, the HER2-low phenotype was more prevalent in triple-negative PAC than in ALC (P < 0.001). Levels of TILs were low (≤10%) in 74% of ApoCa (median: 5%, range 0%–50%). TIL levels were significantly higher in ALC than in PAC (P ═ 0.02). HER2 status had no impact on TIL distribution (P ═ 0.45). The genomic profile of HER2-low ApoCa was similar to other subtypes of ApoCa. ApoCa has predominantly low TIL, particularly PAC. The prevalence of the HER2-low phenotype in ApoCa is high, which should have therapeutic and clinical implications given the recently approved therapies with antibody–drug conjugates (ADCs) for HER2-low breast cancers.

From February 2023 (Volume 23, Issue 1), the title of the Bosnian Journal of Basic Medical Sciences will be changed to Biomolecules and Biomedicine. The new title reflects the increasing number of published research done on subcellular/molecular level as well as translational and clinical research contained in the term Biomedicine. Biomolecules and Biomedicine will continue to be published by the Association of Basic Medical Sciences of the Federation of Bosnia and Herzegovina. Read more in the PDF.

SUMMARY In prostate adenocarcinoma, both tumorous stroma and epithelium have important role in tumor progression. Transforming growth factor beta (TGF- β) is a promotor in advanced stages of prostate cancer. Matrix Metalloproteinase 2 (MMP2), the endopeptidase that degrades extracellular matrix is considered to be overexpressed in prostatic carcinoma related to its growth and aggressiveness. Therefore, the aim was to analyze the expression of proteins TGF- β and MMP2 between both epithelium and stroma of prostatic adenocarcinoma and adjacent unaffected parenchyma. The intensity of TGF- β and MMP2 expression in epithelium, tumorous stroma and adjacent unaffected parenchyma was analyzed in 62 specimens of prostatic adenocarcinoma by microarray-based immunohistochemistry. TGF- β was more expressed in tumorous than in prostate stroma (p =0.000), while no statistical significance in case of MMP2 (p = 0.097) was found. MMP2 was more expressed in tumorous than in prostate epithelium (p =0.000), while no statistical significance in case of TGF- β (p = 0.096) was observed. The study results indicate that both tumorous stroma and epithelium have a role in tumor progression and support potential role of TGF- β and MMP2 in prostatic adenocarcinoma progression.

A 65-year-old woman with a negative family history of breast cancer presented with a palpable mass in the left breast’s central portion. Mammography revealed an oval heteroechogenic, partly solid, partly cystic, sharply demarcated mass, measuring 100×90 mm in greatest diameter, classified as BI-RADS 4c, according to ACR BI-RADS Atlas Fifth Edition (Figure 1A-B). Breast MRI showed a lobulated mass with smooth margins appearing hypointense on T1WI and high signal intensity on T2WI (Figure 1C-D). A core needle biopsy revealed a cellular neoplasm, composed of small, closely packed tubules with spindle cell intervening stroma without prominent atypia and mitotic activity, classified as B3 category according to the UK National Coordinating Committee for Breast Screening Pathology (Figure 2A). The multidisciplinary tumor board discussed the case and recommended a wide surgical excision. With the patient’s approval, a left mastectomy was recommended and performed. The axillary clearance was not performed. The 100×90 mm tumor was grossly well-circumscribed, grayish-white, and predominantly solid, with a smaller cystic component, without necrosis and hemorrhage (Figure 2B). Histopathologic examination revealed a well-circumscribed tumor with two distinct components (tubular adenoma and phyllodes tumor) with the transition to one another (Figure 2C). The larger portion of the tumor was composed of closely packed small round to oval tubules with little intervening spindle cell stroma consistent with tubular adenoma. The smaller component showed a biphasic fibroepithelial tumor with leaf-like projections with moderately cellular stroma (Figure 2D-E). The stromal cells exhibited mild to moderate atypia, and their mitotic activity was up to six mitoses/10 hpf (Figure 2F). Stromal overgrowth was absent, while the malignant heterologous elements were not observed despite the exhaustive tumor sampling (25 paraffin blocks). The final diagnosis was a complex fibroepithelial tumor composed of borderline phyllodes and tubular adenoma. Clinical Science