Transcript per million conversion

Question

[Natasha]

I would like to get advice on how to convert Transcript per Million(obtained from here) to transcript per cell.Also,can we find an estimate of the number of cells present in a tissue from any of the databases?

[Kristoffer Vitting-Seerup]

This cannot be done unless you both have: 1) Spikeins where you know the excact number of molecules (such as the ERCC spikeins) 2) Know excatly how many cells you put into the RNAseq library preperation

The numbers simply vary to much to make a trustworthy estimate. Sorry.