For FF samples, either OCT-embedded tissue blocks or cut frozen tissue sections can be sent. If it is an embedded block, a sufficient amount of dry ice is sufficient for shipping. If sending frozen tissue sections, the following requirements need to be met:
At least 10 10-μm-thick sections or rolls of sections, or tissue blocks of equal thickness, need to be provided for each sample for RNA extraction QC; at least 4 consecutive 10-μm-thick sections of the target location should be provided for formal experimental samples;
When sending samples, 2 frozen tissue sections are labeled, placed back-to-back in a pre-cooled 50mL centrifuge tube, capped tightly, and buried in a sufficient amount of dry ice.

No need.

OCT-embedded tissue blocks can be stored in an airtight container at -80°C for a long period of time. OCT-embedded FF samples on slides can be stored in an airtight container at -80°C for up to 2 months.