We knock out a tumor suppressor gene in mouse to see whether it can promote the spontaneous development of intestine tumor.
We were very happy as we observed some tumour-like lesions in the intestine of homozygous knock out mice. But then we also observed some but less frequent such lesions in even the control mouse (mouse that is cdx2-cre genotype), as shown in the attached picture.
I just wonder what is this? Is this because the genome background of CDX2-cre? Thanks!
Some of them look as if they could be Peyer's patches, if not tumor-like lesions.
I agree with Erik. The photograph does not appear show "tumors". See Fig. 2B in the link below for "tumors".
Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4529369/figure/F2/
Thank you all!
Dear Divaker, thanks for your reference. I notice in the picture there are some such Peyer's patches, so when we counting the tumor number, these should not be included rite? My question is how to distinguish them from tumor, as I showed several case in the attached picture, some times it seems not that easy.
First of all: you should confirm histologically that at least some of your "tumor-like lesions" are indeed tumors - and not just more Peyer's patches (but such a finding could also be interesting). In case that there are really tumors which you may not be able to recognize makroscopically, you should fotograph them and analyze them individually by histology. It should be easy for you to see a difference between lymphoid tissue of a Peyer's patch and an epithelial tumor. In addition, it may then be interesting to see, if these are benign tumors (like adenomas) or malignant carcinomas, or perhaps, different states of tumor development...
At this point you can only speculate to see something different in control and KO mice.
Yes, as Robert said, have a good look at control mice which will have normal Peyer's patches, then you can get experience with the range of what they look like. You may become good at recognizing them.
And then when you have something that you think may be a tumour but you are not sure, you need to fix, embed in paraffin wax, take histological sections, stain them, and view with a light microscope. If not experienced in histology, you'll initially need help from someone who is. You could immunostain with an epithelial marker (or a lymphocyte marker) to be more certain still, but as Robert said, it should generally be easy to tell the difference from a standard "H&E" stain, with just a little practice.
I agree with the above comments. Histology of these growths should give an idea whether these are majority lymphocytes or epithelial cells and whether they have an angiogenic network.
Thank you all for these great suggestions! I will perform HE staining for individual suspected "lesions"
This paper can help you.
http://dx.doi.org/10.1590/S0102-86502009000600011
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