Tumors are odd things. In a laboratory context, they’re quite useful as cell sources or as evidence of cell cycle disruption. Entire branches of microbiology look at the intricacies of tumor biology and the tumor microbiome. We’ve even bred strains of rats and mice that spontaneously develop tumors to make it all the easier to study them. In many cases, at least from my limited perspective, study of tumors is synonymous with the study of cancer, and for good reason. According to statistics reported by the American Cancer Society, around 40% of men and women in the United States will develop some kind of cancer in their lifetimes, and about 20% of men and women will die of it[1]. It’s no surprise, then, that my first and greatest fear when I found out I had a breast tumor was that it was cancerous.
I was two months out from an unrelated surgery requiring a full workup, including a mammogram. Interestingly enough, they didn’t find my tumor on that mammogram (or the targeted follow-up mammogram). It was an odd stroke of dubious luck that uncovered it during an ultrasound. The technician had finished examining the area she’d been directed towards and just happened to move the wand up. A black blob rose like a beast from the depths of white haze, perfectly round and very much unexpected. The tech took measurements from several angles and told me to wait for the radiologist, who assured me it was too small to be worth doing a biopsy. About a week later, I was called and told I would be having an ultrasound guided needle biopsy anyway, just to be safe.
Thankfully, the radiologist was right and biopsy confirmed my tumor isn’t dangerous. I have a 2cm bilobed fibroadenoma, which is a benign overgrowth of glandular and lobular tissue. They’re actually the most common type of benign lump and are most common in women in their 20s and 30s, according to Johns Hopkins[2]. More amusingly, their high mobility has given them the nickname “breast mice.” I think mine kind of looks like a snowman.
Since I’m young, the decision was made to not remove my tumor, so a titanium clip was inserted to mark it as already biopsied. My surgery proceeded as planned, and this adventure came to a close. So why am I bringing it up now? Nobody knows what causes fibroadenoma formation. There has been a casual association made between their occurrence and reproductive hormones, and some studies have shown an increased rate of MED12 somatic mutations in fibroadenomas[3], but no heritable genetic factor has been identified in connection to fibroadenoma generation. Maybe I’m biased, but that seems like a perfectly tantalizing challenge to me. I challenge you, reader, if you’re interested in tumor biology, consider looking into the etiology of benign tumors. Sure, you could cure cancer and win the Nobel Prize…but wouldn’t you rather be able to brag at parties that you figured out what creates breast mice?
Sources:
https://www.cancer.org/cancer/cancer-basics/lifetime-probability-of-developing-or-dying-from-cancer.html
https://www.hopkinsmedicine.org/health/conditions-and-diseases/common-benign-lumps
Lim, W., Ong, C., Tan, J. et al. Exome sequencing identifies highly recurrent MED12 somatic mutations in breast fibroadenoma. Nat Genet 46, 877–880 (2014). https://doi.org/10.1038/ng.3037
Picture source: http://www.smj.org.sg/article/four-cases-echogenic-breast-lesions-case-series-and-review