The lack of a universal method for preparing FFPE tissue samples makes choosing the right supplier a critical component of tissue research. Sample quality varies among suppliers and researchers need to obtain well-annotated tissues to discover answers to their research questions when studying complicated diseases like cancer. Following a few guidelines will help ensure your tissue research leads to clinically useful results.
Your chances of obtaining quality samples are greatly increased if the fixation process is performed under the direction of a licensed pathologist. Pathologists have the education and experience to oversee all aspects of FFPE tissue block production. Pathologists can confirm diagnoses and oversee the preparation of hematoxylin and eosin staining. These physicians also ensure samples contain DNA and RNA that can be used for downstream analyses like PCR and microarray. Genomic integrity must be maintained if samples are to be arrayed. Chemical denaturation can easily occur to an extent that makes molecular analyses impossible.
Quality control of FFPE blocks should be a twofold process. Make sure your supplier performs both gross and microscopic reviews of samples prior to sale.
Sample origin also affects sample quality. Quality control processes vary from region to region so ask about the location from which your sample was obtained. Non-US derived tissue samples are sometimes subject to lower standards of quality and may be inadequately annotated for research involving tissues with a high degree of molecular heterogeneity. This is especially relevant in tumor research.
Transparency is another factor indicative of sample quality. Well-reputed organizations that implement high standards will not hesitate to provide answers to all questions from purchasers. Suppliers who lack answers to your questions or only provide vague responses to specific queries should be avoided.
Providing detailed patient histories is essential for disease-related research projects. Finding a patient cohort that fits within the parameters of your research project can be challenging and time-consuming. Choose a supplier that keeps detailed patient histories of their FFPE samples. Patient histories should include information about gender, diagnosis, staging and resectioning date. If samples are being purchased for research on cancers, make sure that metastatic details are included in the patient histories. These details should include tissue and tumor size as well as tumor type and the percentage of sample consumed by the tumor. Genetic profiling is sometimes offered for common oncogenes and this helps to expedite laboratory workflows. Thorough annotation and detailed patient histories go hand in hand as critical elements contributing to sample quality.
Post-fixation processes can diminish sample quality and quantity. Obtaining blocks that are cut and re-embedded will decrease the amount of tissue you obtain. Find a supplier that provides samples in their state of original fixation.
Quality of customer support is often a good indicator of supplier reliability. Having an educated and knowledgeable support team to answer your questions shows that your supplier is committed to customer satisfaction and maintaining sustained relationships with clients.