32P - Clinical evaluation cancer testis antigen 45 (CT45) expression in ovarian cancer

Background

Ovarian cancer (OC) is the 3^rd deadliest gynecological cancer worldwide. CT45 reacts with platinum to prolong the overall survival that we evaluated here.

Methods

In 62 cases of high-grade serous carcinoma (HGSC), pre-therapy serum and intra-operative tumor tissues were collected. We had 35 upfront surgeries and 27 neo-adjuvant chemotherapy cases. A cutoff for the serum level of CT45 was established to differentiate cancer and healthy (N=25) individuals using ROC curve analysis as 0.77 ng/mL at 91% sensitivity and 65.2% specificity and P value 0.015. The mean value for cancer and healthy samples was 1.09 ng/mL and 0.69 ng/mL respectively. A cut-off of fold change 1.00 was used for tissue expression in qPCR.

Results

CT45 expression in ovarian tissue (N=62): Out of 62, 22 (35%) cases had high expression, and 40 cases had low expression (65%). In low-expression cases, 14/40 (35%) cases showed recurrence. The median fold change in recurrent vs. non-recurrent cases was -3.59 and 0.23, respectively. Among high-expression cases, 6/22 (27.2%) had recurrence. The median fold change in recurrence and non-recurrence cases was 7.56 and 111.8, respectively. Looking at the difference, a cut-off of 9.51 was established to differentiate between recurrent and nonrecurrant cases (P < 0.0001) using ROC curve analysis at a sensitivity and specificity of 89% and 88.24%, respectively. Above this value, no case showed recurrence for at least 2 years. Among all 62 cases of HGSC, 28 (45%) had a fold change of >9.51. Serum levels of CT45 (N=31): Serum level of CT45 was measured in 31 patients. The high and low values were seen in 16/31 (51.6%) and 15/31 (48.3%), respectively. Recurrence was seen in 12/31 cases. The mean serum CT45 in recurrent cases was 1.11 ng/mL (median 0.83 ng/mL), while in non-recurrent cases it was 0.60 ng/mL (median 0.17 ng/mL).

Conclusions

Patients with high CT45 (>9.51-fold change) showed no recurrence and a better prognosis in all the HGSC cases of ovarian cancer. This is the first study on CT45 expression in ovarian cancer that shows a specific cutoff of 9.51 for the prediction of recurrence following platinum-based chemotherapy. The serum level of CT45 showed no clinically significant result.

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

The authors.

Funding

AIIMS, New Delhi.

Disclosure

All authors have declared no conflicts of interest.