Evaluation of Immunohistochemistry and H&E Staining for Detection of Tumor Budding in Colorectal Cancer

Abstract

Background/ Objective: Tumor budding (TB) is an established prognostic marker in colorectal cancer (CRC) and is defined as single tumor cells or clusters of up to four cells at the invasive front. While the International Tumor Budding Consensus Conference (ITBCC) recommends hematoxylin and eosin (H&E) as the standard for TB evaluation, immunohistochemistry (IHC) with pan-cytokeratin may improve detection in histologically challenging cases. The current study aims to compare TB assessment using H&E and pan-cytokeratin IHC and evaluate its association with clinicopathological parameters in CRC.

Methods: A retrospective analysis was conducted on 98 CRC cases resected between 2017 and 2022. TB was graded according to ITBCC 2016 criteria on H&E and cytokeratin-stained sections (clone AE1/AE3). Associations with clinicopathological features were analyzed using Chi-square or Fisher’s exact tests, with p ≤ 0.05 considered significant.

Results: On H&E, TB was positive in 61 cases (62.2%): Bd1 (29.6%), Bd2 (15.3%), Bd3 (17.3%). On IHC, TB was positive in 67 cases (68.4%): Bd1 (32.7%), Bd2 (19.4%), Bd3 (16.3%) (p < 0.001 for increased detection). High TB (Bd2–Bd3) correlated significantly with advanced pathological stage (p < 0.001), higher T stage (p < 0.001), lymph node metastasis (p < 0.001), vascular invasion (p = 0.002), perineural invasion (p = 0.003), and desmoplasia (p = 0.017).

Conclusion: Pan-cytokeratin IHC improves TB detection compared with H&E, especially in morphologically complex areas, and high TB is strongly associated with aggressive tumor features. Selective IHC use may enhance diagnostic accuracy and prognostic assessment in CRC.

Keywords: tumor budding, colorectal cancer, immunohistochemistry, pan-cytokeratin, H&E, prognosis