I'm not familiar with these cell lines but I did a little bit of digging and there are some curious anomalies. First of all RPMI 8226 but not RPMI 8266 can be found in the ATCC catalogue for purchase. RPMI 8226 was first mentioned in a publication in November 1970 and also named the 'Simpson' cell line (https://www.ncbi.nlm.nih.gov/pubmed/18605421).

RPMI 8266 is first mentioned in 2001 in this publication, https://www.ncbi.nlm.nih.gov/pubmed/11568006, but it seems they made a mistake in naming the cell line. In the abstract they mention that they used 3 MM cell lines for their study: U266, RPMI-8266, and NCI-H929. But in the material and methods section they state that..."Human U266, NCI-H929, and RPMI-8226 MM cells were obtained from American Type Culture Collection (ATCC, Rockville, MD) and cultured in..." Then they interchangeably call the cell line by one of those two names.

Also, there are 591 papers on PubMed that name RPMI-8226 dating back to 1970 and only 9 publications dating back to 2001 that name RPMI-8266. Since the first publication to name RPMI-8266 stated that they purchased the cells from ATCC which only sells RPMI-8226, I suspect that this mistake propagated the same cell line by 2 different names. As I have no knowledge of MM cell lines I could be wrong but to me it seems that they are the same cell line which had its named mixed up in a few publications starting in 2001.

That makes sense! I was also leaning towards the same conclusion, but wasn't too sure. Thank you very much for taking the time to answer, Pawel!

Hi,

Misspelling of cell lines is quite common. Currently I noted down in the Cellosaurus 333 cell lines that have been misspelled in literature or data resources:

http://web.expasy.org/cgi-bin/cellosaurus/search?input=misspelling

A number of RPMI cell lines are among those that get misspelled as people often scramble numbers (dyslexia!) and I had already noted that RPMI-8226 had been misspelled as 'RPMI-8266'. See:

http://web.expasy.org/cellosaurus/CVCL_0014

I will now, thanks to this discussion, add 'RPMI-8266'.

As Pawel noted the oldest mention of 'RPMI-8266' is from 2001: 9 years after the Roswell Park Memorial Institute (=RPMI) had been renamed to Roswell Park Cancer Institute (=RPCI):

https://en.wikipedia.org/wiki/Roswell_Park_Cancer_Institute#Previous_names

So this also "proves" that RPMI-8266 is an erroneous designation for RPMI-8226.

By the way, a small correction on Pawel answer. As noted in the Cellosaurus entry, the paper describing the establishment of this cell line is not the one of Ikeuchi in 1990 but a paper from 1967 from four RPMI scientists:

https://www.ncbi.nlm.nih.gov/pubmed/6042436

This paper describes the patient (a 61 year old man) and the establishment of the cell line:

"The cell culture became self sustaining and was designated as RPMI #8226"

Best regards

Amos