Dear Participants, As we progress to the test phase, we want to share a quick reminder regarding challenge rules and offer a note on submission strategies to help everyone get the best results on the final test set. ###Single-Account Policy & Integrity To maintain a fair and collegiate competitive environment, we remind all participants that each team is strictly allowed only ONE team account for this particular challenge. **Policy Clarification**: Registering or using secondary accounts to bypass daily submission quotas is a direct violation of the challenge terms and research guidelines. **Community Trust**: Validation quotas are set to encourage thoughtful, deliberate experimentation. We rely on all participants to uphold standard scientific integrity and adhere strictly to the single-account policy. ###Validation Probing vs. Test Set Generalization We have noticed various submission patterns on the validation leaderboard. While it can be tempting to use daily validation submissions to fine-tune models against the validation score, please keep in mind: **Distribution Differences**: The upcoming test set differs from the validation set in terms of patient cohorts, label frequencies, and data sources. **Risk of Overfitting**: Over-optimizing your model to the specific nuances of the validation set will likely lead to poor generalization on the final evaluation set. The validation leaderboard is meant as a simple assessment for your pipelines—the most robust, generalizable methodologies will ultimately perform best when the final test phase opens. Thank you all for your hard work, vigilance, and dedication to keeping this challenge fair and competitive. If you have any questions regarding team merging or account configurations, please reach out to the organizing committee. Best of luck with your models! BraTS Pathology Organizing Committee