Multicentric Squamous Cell Tumors in Panther Chameleons (Furcifer pardalis)

 

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Panther Chameleons

Squamous cell carcinoma is a common tumor found in many animals, including Furcifer pardalis. Otherwise known as the panther chameleon, they are kept as exotic pets as many, although native to Madagascar. Squamous cell carcinoma (SCC) is a malignant growth that affects the squamous epithelium of the skin. The development of this malignancy is classically associated with damage to the tissue, including UV lighting that is too strong, and viral infection. Most notably, viral infection such as papilloma viruses can predispose a chameleon to scale and epithelial tissue damage. In this study, various aged male panther chameleons (sub-adult to senior-aged) were identified to have epithelial disturbance. Immunologic response can be altered using the drug Imiquimod, which modifies the immune response to non-surgically remove the mass. Additionally, surgical resection can be performed, although difficult given the size and anatomy of the chameleons. Researchers mention that although the small, it is important to consider the implications. I believe that researchers should also investigate whether selective breeding for color on these beautiful creatures may impact cancer and malignant tumor rates in chameleons, as well as other selectively bred pets. 

Cancer Clues

Genetic clue's can now be used to predict whether early-stage cancer will form an invasive tumor. One type of non-invasive tumors, Carcinoma In Situ or (CIS), that occurs within the lungs can either remain noninvasive or progress into an invasive form known as Lung Squamous Cell Carcinoma (LUSC). Until recently scientists were unable to predict which CIS growths would persist. But now a a set of genomic alterations from a lung tissue sample can readily anticipate which tumors will become invasive. 129 lung tissue biopsy's were studied through a range of genomic anaylses including whole-genome DNA sequencing, analysis of RNA expression, and profiling of a DNA modification called methylation that can influence gene expression. Within the whole-genome sequencing 29 samples progressed to LUSC while 10 regressed to CIS. Almost all of the progressive samples had mutations in the tumor suppressor gene, TP53. The progressive samples also acquired a distinct pattern of chromosomal amplifications and deletions of sequences that are commonly found in squamous cell carcinomas. The regressive CIS generally lacked these chromosomal aberrations. A statistical method of analysis was further used to demonstrate that DNA methylation patterns in the regressive CIS samples were more similar to those of normal lungs in comparison to the patterns within a progressive tumor. While scientists were able to target the differences in mutations between CIS and LUSC, the reason for progression is still unknown. We can pin point which CIS growths will persist, yet we do not know which changes are essential for the invasive cancer to form. The evolution of CIS to form invasive carcinomas have also been studied in Breast cancer and continue to make remarkable advanced in early detection. I find this discovery very exciting and possesses a ton of potential to help treat patients before the non-invasive tumors become invasive and life-threatening. 

New way to Identify Individuals at Greater Risk for Developing Cancer

The genes we have for determination of the colour of our eyes and hair and how our bodies grow might also influence the changes that occur in tumors when we develop cancer.
According to researchers at the Ohio State University, our normal genetic background that is the genetic variations that we inherit contributes to different DNA changes that occur in tumor cells as cancer develops.
Multiple independent tumors from people with a form of skin cancer called squamous cell carcinoma (SCC) were compared for losses and gains of DNA in tumor cells. The results showed that the pattern of these changes is quite similar in tumors from the same person but quite different in tumors from different individuals. This study may offer a new way to identify individuals at greater risk for developing cancer. They found that the changes in SCCs from the same patient were statistically similar but significantly different when compared with other patients. They also found that in some cases a particular kind of genetic change is preferentially selected in tumors from the same individual.
These studies provide strong evidence that an individual's genetic background plays a key role in driving the changes that occur in tumors during cancer development.