Laboklin have announced a new DNA test for Squamous Cell Carcinoma of the digit / toe (SCCD) in Giant Schnauzers, which sounds like good news but, whilst it could be helpful, it does not give the certainty of ‘clear’ ‘carrier’ or ‘affected’ test results as with prcd-PRA, DCM, PRA5 etc (which are inherited recessively).
The test looks at the number of copies of the KIT Ligand (KITLG) gene variant, thought to be associated with digital squamous cell carcinoma (dSCC) susceptibility. It provides an approximation of the number of copies of the KITLG gene variant which gives a risk classification of:
medium (4.7- 5.8)
Independent expert opinion obtained earlier this year, advised that whilst the test may be useful as an assessment of individual dogs’ risks, as it may help owners to pay attention to the digits in those at increased risk, caution is advised against using the test in making breeding decisions until more is known. Some dogs with high copy numbers (typically associated as at risk) have been shown not to develop the condition, and there have also been sporadic cases of dogs with low copy numbers affected with dSCC.
Aupperle-Lellbach et al, 2023  also summarised that including the mutation (KITLG CNV) in breeding decisions will be complex, but the diagnostic test may help to assess the individual risk for dSCC and to sensitise owners of black GS accordingly if the CNV value is high.
It has also been suggested that the frequency of the KITLG CNV may be high in Giant Schnauzers. The same research paper showed that most Giant Schnauzers had more than four and up to seven copies of this gene segment, in which case an independent expert advised that using this test for making breeding decisions may be risking a catastrophic reduction in genetic diversity.
The paper went on to state further studies with higher case numbers are needed to confirm the results of the pilot study. The full text for the study, and on which the DNA test is based, can be found on the following link:
 Aupperle‐Lellbach, H. et al. (2023) ‘KITLG Copy number germline variations in Schnauzer breeds and their relevance in digital squamous cell carcinoma in black giant Schnauzers,’ Veterinary Sciences, 10(2), p. 147. https://doi.org/10.3390/vetsci10020147.