How much tissue is required to customize the FFPE tissue chip with the wax blocks provided by yourself?

We provide wax blocks to make customized chips. It is recommended to do one-step donor block screening first: cut each of the 40 colorectal cancer wax blocks into a sheet of HE, and ask the pathologist to evaluate the proportion of tumor cells and whether there are enough adjacent to the cancer. Although some wax blocks are large in area, they are necrotic or heavily fibrotic, and there is no signal to hit them. The tissue volume of the 2mm dot diameter is sufficient, but the chip receptor block needs to be sliced again after dotting, and the flatness of the slice surface is affected by the sampling depth. Before production, ask the supplier to produce an array diagram to confirm the source and location of each point to avoid subsequent staining results.

Tissue volume requirements mainly look at the effective tumor area, with a point diameter of 2mm and 2 points. It is recommended that the target area in each wax block can accommodate at least two non-overlapping 2mm tissue cores, leaving a margin around the periphery. Generally, the effective area is preferably greater than 5 × 5mm. Wax blocks that are too thin or fragmented can easily fail to form a complete tissue column. Before delivery, it is best to have the pathology colleagues circle the tumor and normal area, and evaluate the supplier together with the HE biopsy first to avoid blanking. If the surface of the wax block is uneven or too thin, some companies will re-embed it and then make a point.

Both quote methods are available, but it is more common for customized chips to be priced by the point, and slicing and quality control are calculated separately or include the first one. Therefore, when inquiring for quotation, do not only ask "how much money per point", but also confirm whether the dot fee includes the production of receptor blocks, whether it includes the sampling and positioning of donor blocks, whether the first round of slices will be given, whether HE quality control will be charged, and whether the remaining wax blocks and excess slices will be saved and sent back. Avoid late payouts. In addition, if you hit 2 points per wax block, you can make a tumor and normal pairing point, so that later analysis is more reliable, not necessarily the same charge for each point.

The production cycle is usually 2-4 weeks, don't be too tight. The process includes donor wax block evaluation, array design, dotting, receptor block embedding, slicing, HE quality control, and may require replenishment due to insufficient wax block tissue in the middle. 40 colorectal cancer wax blocks are 2 points each, the workload is not small, and it is recommended to reserve at least 3-4 weeks. If it is urgent, you can ask if there is an expedited service, but expediting may reduce the quality control time. Quotes are usually counted, and some are packaged according to the number of slices in the final delivery. The quotation must indicate which services are included.