Tumor budding in colorectal cancer (CRC) is recognized as a valuable prognostic factor but its translation into daily histopathology practice has been delayed by lack of agreement on the optimal method of assessment. Within the context of the Swiss Association of Gastrointestinal Pathology (SAGIP), we performed a multicenter interobserver study on tumor budding, comparing hematoxylin and eosin (H&E) with pan-cytokeratin staining using a 10 high power field (10HPF) and hotspot (1HPF) method. Two serial sections of 50 TNM stage II-IV surgically treated CRC were stained for H&E and pan-cytokeratin. Tumor buds were scored by independent observers at six participating centers in Switzerland and Austria using the 10HPF and 1HPF method on a digital pathology platform. Pearson correlation (r) and intra-class correlation coefficients (ICC) comparing scores between centers were calculated. Three to four times more tumor buds were detected in pan-cytokeratin compared to H&E slides. Correlation coefficients for tumor budding counts between centers ranged from r = 0.46 to r = 0.91 for H&E and from r = 0.73 to r = 0.95 for pan-cytokeratin slides. Interobserver agreement across all centers was excellent for pan-cytokeratin [10HPF: ICC = 0.83 and 1HPF: ICC = 0.8]. In contrast, assessment of tumor budding on H&E slides reached only moderate agreement [10HPF: ICC = 0.58 and 1HPF: ICC = 0.49]. Based on previous literature and our findings, we recommend (1) pan-cytokeratin staining whenever possible, (2) 10HPF method for resection specimens, and (3) 1HPF method for limited material (preoperative biopsy or pT1). Since tumor budding counts can be used to determine probabilities of relevant outcomes and as such more optimally complement clinical decision making, we advocate the avoidance of cutoff scores.

It is well known from the older literature that gastric carcinomas are more likely to develop in a stomach containing hyperplastic polyps. The reason why such a stomach should represent a precancerous condition is, however, largely unexplained. The aim of this study was to determine the disorders of the gastric mucosa in which hyperplastic polyps occur. In 244 patients with hyperplastic polyp, in whom at least two additional biopsies each from the antrum and corpus were available, gastritis was classified on the basis of the updated Sydney System. In none of the 244 patients was the gastric mucosa found to be normal. The most common disorder, at 51.3%, was autoimmune gastritis of the corpus mucosa, while chronic active Helicobacter pylori (Hp) gastritis was seen in 37.3% of the patients. Of the patients with Hp gastritis, 56.1% had corpus-dominant Hp gastritis. Other forms were relatively rare: when A-gastritis, corpus-dominant Hp gastritis and any other form of Hp gastritis were lumped together as a precancerous condition, these changes were found in 88.6% of the patients with hyperplastic polyps of the stomach. In the presence of hyperplastic polyps of the gastric mucosa, additional biopsies obtained from the antrum and corpus should always be performed to obtain a basis for deciding whether to apply Hp eradication treatment as potential carcinoma prophylaxis.

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Abstract.A glycine to valine substitution at codon 12 (G12V) in Kirsten-Ras (K-Ras) gene has been associated with reduced overall survival in colorectal cancer patients; however, the effect of other K-Ras mutations than G12V still remains unclear. Therefore, we investigated the role of different K-Ras mutations on overall survival in a homogeneous, large patient cohort with standardized therapy and uniform analysis of K-Ras mutation status. The study included 342 patients with histopathologically proven colorectal cancer. Survival data were provided by the federal agency for statistics in Austria. Occurrence of K-Ras mutations at codons 12, 13 and 61 were determined by capillary sequencing. The overall K-Ras mutation frequency in carcinoma tissue was 28%. Carriers of the G12V mutation at the K-Ras gene showed a significantly decreased overall survival compared to carriers of the wild-type [HR=2.56 (1.15-5.69)]. Other mutations than G12V were associated with better overall survival compared to wild-type [HR=0.44 (0.2-0.99)]. In conclusion, for the first time, our study showed clearly that different types of K-Ras mutations are conversely associated with overall survival in patients with colorectal cancer.

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