Pre-analytical conditions affect histomorphology and biomarker assessment in invasive breast carcinoma

Background Standardization of the pre-analytical phase, including prompt specimen sectioning and appropriate fixation, is essential for preserving tissue morphology and protein integrity. However, these practices are not consistently implemented in many pathology laboratories, particularly in resource-limited settings. This study aimed to compare histopathological features and predictive biomarkers in invasive breast carcinomas processed under optimal conditions versus routine conditions. Methods A total of 49 surgical fresh specimens of breast cancer were grossly examined and bisected. A representative tumor fragment from each specimen (1.0 × 1.0 × 0.2 cm) was immediately fixed in 10% neutral buffered formalin for 24 h (Group 1: early sectioning with buffered formalin fixation). The remaining specimen was reassembled, placed in non-buffered formalin, and transported to the laboratory according to routine workflow, with delayed sectioning (24–48 h; Group 2: delayed sectioning with non-buffered formalin fixation). A second sample of tumor was obtained from each delayed sectioned specimen (total: 49 samples) on the opposite side of previous sectioning. Histopathological evaluation included autolysis-related morphological changes, histological tumor type, and tumor grade. Immunohistochemical analysis of the estrogen receptor (ER), progesterone receptor (PR), and HER2 were performed. Results Autolysis-related morphological changes were significantly more frequent in Group 2 than in Group 1 (33.3% vs. 12.5%, p = 0.02). Special histological types were more frequently identified in Group 1 ( p = 0.03). No significant differences were observed in histological grade or ER and PR expression. HER2-negative status was more frequent in Group 2, whereas equivocal (2+) cases were more common in Group 1, although without statistical significance. Conclusions Delayed sectioning with non-buffered formalin fixation is associated with increased autolysis-related morphological alterations and may affect histological tumor classification of invasive breast cancer. ER and PR expressions appear relatively stable, while HER2 is more susceptible to pre-analytical variability, underscoring the importance of optimized specimen handling.