# Comparative Analysis of COL9A1 Genotyping in Oral Squamous Cell Carcinoma Diagnosis: A Pilot Study
## 4 Discussion
Their results suggest that the COL9A1 gene contributes to continuous cell proliferation in head and neck cancer and demonstrates a higher expression in the case of the tumours in the setting of metastasis compared to those without dissemination. Moreover, by analysing the expression of COL9A1 in HNSCC cell lines compared to normal mucosal epithelial cell lines, it was concluded that the existence of the overexpression of the gene was due to the fact of increased expression in the transformed epithelial cell components of the tumour [27 ]. Another evaluation of increased expression of COL9A1 in tumour-derived fibroblasts from tissue explants compared to fibroblasts obtained from healthy individuals showed higher levels of COL9A1 in the HNSCC fibroblasts from tissue explants compared to healthy ones. The normal fibroblasts in response to a wound secrete different types of collagens, among which is COL9A1 [27 ]. A large number of gene mutations have been associated with OSCC and described in the Cancer Genome Atlas, and several were linked to the initiation process as well as the progress of oral squamous cell carcinoma [27 ]. In our study, we targeted the COL9A1 gene that had a mutation rate higher than 20%, with various mutation variants that have been encountered in the developmental process of OSCC [27 ]. Unfortunately, OSCC is still diagnosed in advanced stages and associated with a high mortality rate. Early diagnosis in this case and minimal invasive treatment options should be the target of further research. This pathology should be revised using genetic information and associated environmental risk factors. A study conducted by [PERSON] et al. revealed that early detection of oral premalignant disorders reduced the diagnosis of stage III and IV oral cancer by 21% [27 ]. A study performed by [PERSON] et al. [27 ], which focused on variants of COL9A1 and FAT1 gene variants in the male population and also added risk factors related to oral malignancy, reported that a high genetic risk score was associated with the incidence of OSCC by up to 92%. Their genetic score was based on genotype analysis and the presence or absence of the T allele combined with risk factors (cigarette smoking, betel and alcohol), for both the OSCC group and the controls. This was the first study that focused on the possible association of the COL9A1 gene and the occurrence of OSCC based on tissue sample analysis. The identification of COL9A1 genotypes associated to the OSCC group was 37.8% for the C/T genotype and 18.9% for the T/T genotype, while the C/C genotype was 43.3%. In the case of our pilot study, the results for the male group related to the identification in the tumour sample of the C/T genotype was 55% and for the T/T genotype 35%. In addition, our results can be explained by the difference in the study group numbers. The habit of smoking in their OSCC group was 86.9%, similar to our percentage among the male group which represented 80%. Related to alcohol consumption in the male population, [PERSON] et al. stated that 68.1% of subjects consumed alcohol, also comparable with the results of our study that reported a 65% incidence of alcohol consumption among the OSCC male group. Compared to their study, we decided to introduce both genders, and the COL9A1 genotypes in the female OSCC group were also present. The hypothesis of our pilot study gravitated around the theory of an existing relationship between the COL9A1 gene variant C/T encountered in tumour tissue and blood samples of patients. The main limitation of this research consisted of the number of patients, but as a primary attempt to identify a connection between the two types of samples, our results are promising. Our pilot study focused on the correlation and the presence of the gene mutation in blood and tissue samples, with a positive significant statistical correlation (\(p<0.001\)) between the samples. These results are encouraging for a future study including a higher number of subjects.