Cancer is a leading cause of death worldwide andthis is at least in part due to limitations in current therapies and late diagnosis. Thus, improving the tools to diagnose cancer at early stages and the development of new therapeutic targets is essential. One group of proteins that might be helpful for both diagnosis and immunotherapy targeting is known as the cancer/testis antigens (CTAs). CTA genes are expressed in the normal testis and should not be expressed in other healthy somatic cells,however these genes are expressed in various cancer cells. Therefore, identifying new bona fide CTA genes has great clinical importance. In this study, different strategies were used to identify and characterise new CTA genes. The results presented here identified eleven candidate CTA genes. Two CTA genes, SPO11and PRDM9were validated at the protein level. SPO11 and PRDM9 proteins were detected only in the normal testis and not in any other normal tissues. PRDM9 was detected in different types of cancer and SPO11 was detected in all the cancer cell lines and most of the cancer tissues which were used in this study. These results suggest that SPO11 might be essential for the cancer cells. SPO11 was also found to be associated with the DNA, which might indicate that SPO11 was bound to the DNA, giving rise to the possibility of DSB formation in cancer cells. The presence of SPO11 during mitotic cell division might lead to incorrect replication or/and formation of DSBs during mitosis, which might lead to different chromosome rearrangements and ultimately to cancer,suggesting that SPO11 could be anoncogenic driver. Therefore, defects in SPO11 might cause cancer cells to undergoapoptosis, which might explain the level of cell death observed after the cancer cells were treated with siRNA and TALENs. In addition, knockdown of PRDM9 was shown to reduce SPO11-DNA binding in the cancer cells which suggested that PRDM9 may have a meiotic-like functionin cancer cells, which opens the chromatin and allow SPO11 access and DSB formation. CTA genesare important during meiosis. Identification of new CTA genes expressedin different cancer tissues and cell lines indicate that they may be potentially good tools for early diagnosis or/and cancer therapy targets.