No evidence for the involvement of XMRV in the pathogenesis of breast cancer

Looks like another negative study... but read on.

http://www.nature.com/bjc/journal/vaop/ncurrent/full/bjc201251a.html

Do I read this correct? 6 out of 6 and 12 out of 12 positive for XMRV?

Eh? I read 4 out of 6 and 2 out of 12?

I missed this

Now I think there were 4 MCC samples positive for MCV and 2 prostate cancer samples positive for XMRV

So, another positive XMRV study.

I haven't got access to the full paper, but this study is interesting because the negative results for the breast cancer samples suggest that the lab is not contaminated. Although, without reading the paper, it's not possible to tell if all samples were handled in the same way.

They should have looked for the mouse mammary tumour virus in the breast cancer samples.

From the Khan et al. paper.

"In this study,we found 2 of the 12 prostate samples to be positive for XMRV. One of the two XMRV amplified products was subsequently sequenced and clearly identified as belonging to XMRV VP62 genome. However, the sequence amplified in our case had several mutations compared to XMRV VP62 genome, suggesting that the source of XMRV in this sample was not due to contamination from plasmid XMRV VP62 used as a positive control.

We had limited material from these two XMRV-positive prostate samples, and as such we were not able to confirm our findings using alternative primers targeting separate regions of XMRV. Thus, the possibility that the single nucleotide differences found in our case is due to sequencing errors cannot be excluded."

BLASTed XMRV sequence from the one prostate cancer patient in the Khan et al. paper. The closest match was to a Lo et al. PNAS sequence: "CFS isolate BD-22".

Eco

Very interesting, thank you Eco.

CFS isolate BD22 is a polytropic mERV gag gene.
Incidentally BD22 is not a CFS patient, but a healthy blood donor.

We are expecting the env viral sequence found in PWME to be polytropic not xenotropic.