Recently, we have injected s.c. B16F10 tumor cells in BL/6 mice. At around 12-15th day some animals showed ulcerations in tumors , with a big hole in the middle (it looks like a volcano). We have also observed this problem in MC38 and EG7 tumors. This did not happen to us so often until now. Any suggestion or personal experience that helps us to resolve this issue will be really appreciated. Thanks in advance.
Yeah, it is actually not rare. We just use less cells and/or with matrix. This paper might give you some clues.
Int J Exp Pathol. 2015 Apr; 96(2): 73–80. Published online 2015 Feb 9. doi: 10.1111/iep.12114PMCID: PMC4459798PMID: 25664478
Behaviour of four different B16 murine melanoma cell sublines: C57BL/6J skin
By the way, which B6 was used in your experiments? B16F10 (ATCC® CCL-6475™) is from a C57BL/6J mouse. Sometimes, 6J and 6N are very different.
Good luck
Thank you for your answer. I will read the papers that you mention.
But this problem is something that is recently happening, and the tumor cell lines come from old frozen vials.
For an injection of 1x10e6 B16F10 we found day 12-14 there is occasionally some ulceratiin of tumours but it also when we reach the ethical limits of tumour size and the end of the experiment. This has been the case for these tumours for the last 10 years in the lab even with fresh, newly sourced cells vs old cells frozen for years. If you want to take them out longer then use less cells to start with.