The same four cases were found to have mutated metastases. DISCUSSION In this study we show that this concordance between VE1 and BRAFV600E mutations as well as the inter-observer agreement of VE1 is high. using a tissue microarray generated from all available blocks (= 100 blocks). Results Inter-observer agreement was 100% (kappa = 1.0). Concordance between VE1 and V600E mutation was 98.5%. Cohort 1: VE1 positivity (seen in 13.5%) was associated with older age (= 0.0175) and MLH1 deficiency ( 0.0001). Cohort 2: GW6471 VE1 positivity (seen in 12.8%) was associated with female gender (= 0.0016), right-sided tumor location ( 0.0001), higher tumor grade ( 0.0001) and mismatch repair (MMR)-deficiency ( 0.0001). In survival analysis, MMR status and postoperative therapy were identified as possible confounding factors. Adjusting for these features, VE1 was an unfavorable prognostic factor. Preoperative biopsy staining matched resections in all cases except one. No heterogeneity was found across any primary/metastatic tumor blocks. Conclusion VE1 is usually highly concordant for V600E and homogeneously expressed GW6471 suggesting staining can be analysed on resection specimens, preoperative biopsies, metastatic lesions and tissue microarrays. = 8) and melanoma (= 23) cases were correctly detected by all observers. Prognostic cohorts Cohort 1 (Munich, Germany) Cohort 1 was comprised of primary colonic carcinomas (no rectal cancers) from stage I-IV patients. Of the 259 patients included on the tissue microarray (six Rabbit polyclonal to PLAC1 punches per patient), 224 (86.5%) were VE1 negative and 35 (13.5%) were VE1 positive. Of these positive cases 3 (8.6%) showed a weak expression. Patients with VE1 positive cancers were more likely to be older (69.4 years compared to 64.3 years; = 0.0175) and had more frequent MLH1 deficiency (45.7% of VE1 positive versus 4.5% VE1 negative cases; 0.0001). There was no effect on survival. However, within the metastatic patients only, VE1 positivity was associated with significantly worse overall survival (median 4.5 months versus 24 months; 0.0001). Of note, only four patients had concomitant VE1 positive staining. Results are summarized in Table ?Table11 and Figure 3a, 3b. Table 1 Association of VE1 staining with clinicopathological features and survival time in Cohort 1 (German cohort, only colon cancers) 0.0001), c. Swiss cohort- mismatch repair (MMR)-deficient patients (= 0.0624), d. Swiss cohort- MMR-proficient patients, e. Swiss cohort – non-metastatic patients receiving postoperative therapy, f. Swiss cohort- non-metastatic patients not receiving postoperative therapy (= 0.0225). Cohort 2 (Bern, Switzerland) Cohort 2A: VE1 in a multi-punch tissue microarray of 226 colorectal cancer patients (resections) Colorectal cancers from 226 patients were mounted onto a multi-punch 0.6 mm core tissue microarray, including 195 VE1 negative (87.1%) and 29 VE1 positive cases (12.8%). Weak staining occurred in 3/29 positive cases (10.3%). Results are found in Table ?Table2.2. All cores from the same patient stained identically (all positive or all unfavorable). Patients with VE1 positive staining tended to be older (75 versus 70 years; = 0.0768), were more likely female (= 0.0016), had a higher frequency of mucinous cancers (= GW6471 0.0662) and right-sided tumor location ( 0.0001). Tumors were of higher tumor grade ( 0.0001), had significantly more intratumoral budding (= 0.0044) and had a significantly greater frequency of MMR deficiency ( 0.0001). There was no survival difference in univariate analysis. We next looked at MMR-deficient versus proficient cases. As seen in the Kaplan-Meier plots (Physique ?(Physique3c,3c, ?,3d),3d), VE1 appears to have a negative prognostic effect in MMR-deficient patients (= 0.0624), although this result did not reach statistical significance, likely due to the small sample size. Secondly, evaluating postoperatively treated versus untreated patients, VE1 appeared to play a more important role only in the untreated patient subgroup (= 0.082). Since also palliative patients are included in the treatment group, we performed a final analysis on non-metastatic/treated and untreated patients and saw comparable, albeit significant results (= 0.0225) (Figure ?(Physique3e,3e, ?,3f).3f). This unfavorable prognostic effect was maintained after adjusting for pT and pN (Table ?(Table33). Table 2 Association of VE1 staining with clinicopathological features and survival in Cohort 2 (Swiss, colon and.