Insights on Aromatase Immunohistochemistry: Variations between Intrinsic Molecular Subtypes of Breast Cancers

Abstract

Context. Aromatase is a key enzyme in local estrogen production by androgen conversion, especially in women post-menopause. There have been controversies concerning aromatase localization in breast carcinomas and its association with current histopathological variables. Material and Methods. Using polyclonal antibody immunohistochemistry we assessed (by intensity and percentage scores) the immunolocalization of aromatase in 70 tissue samples, and described particularities within the molecular subtypes of breast cancer. Results. Aromatase was found in all tissue compartments: tumor (95.7%), stroma (58.6%) and adipose tissue (94.3%). Aromatase expression in tumor cells correlated inversely with tumor grading (p=-0.361, p=0.027), and positively with estrogen receptor status (ER, p=0.143, p<0.001). Dividing the study group by intrinsic subtypes, a strongly inversely association between tumor aromatase and grading (p=-0.486, p<0.001), and between stromal aromatase and Ki67-index (p=-0.448, p=0.048) was observed in luminal A breast cancer. Tumor aromatase and ER percentage scores had stronger correlations in luminal B HER2 negative (p=0.632, p=0.002), and positive (p=0.324, p=0.026) tumors. In contrast, in triple negative tumors, a positive association stromal aromatase and Ki67 index (p=-0.359, p=0.007) was observed. Conclusion. Local aromatase was linked to better tumor differentiation and proliferation in luminal breast subtypes, and not in triple negative cases, suggesting a potential prognostic role of aromatase in breast carcinomas.

Evaluation of aromatase as a potential biomarker and its association with CA 15-3 in patients with non-metastatic breast cancer

“…Currently, the breast cancer cases which may benefit of endocrine therapy are selected based on estimates of hormone receptors in resected tumor tissues, instead of directly assessing aromatase. The development of anti-aromatase antibodies with raised specificity and sensitivity made possible to best describe of aromatase immunoreactivity in tissues (Armasu et al, 2020).…”

Efecto de los andrógenos sobre la rugosidad, a nivel nanométrico, de la membrana plasmática de células de cáncer de mama triple-negativas

“…Por este motivo, en experimentos in vitro se prefiere el uso de DHT por su alta especificidad al AR y mayor potencia biológica debido a su alta afinidad (Glaser y Dimitrakakis, 2015;Tiefenbacher y Daxenbichler, 2008). Muchos tipos de CaM tienen la capacidad de sintetizar E2 a partir de T, ya que expresan la enzima aromatasa (Bulun et al, 2009), incluyendo el CMTN (Armasu et al, 2020).…”

“…Los andrógenos se identifican por ser compuestos orgánicos liposolubles, por lo tanto, se transportan en el plasma sanguíneo unidas a una proteína de unión al suero, como la globulina transportadora de hormonas sexuales (SHBG). Dichas proteínas protegen a los andrógenos para que no sean degradados, ya que, de no existir esta protección se acortaría su vida media (Armasu et al, 2020;Glaser y Dimitrakakis, 2015). Aproximadamente entre el 60% al 75% de la T sérica se une a la SHBG, mientras que alrededor del 20% al 40% se une a la albúmina y solamente del 1% al 2% está libre.…”