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P1.06 - Poster Session 1 - Prognostic and Predictive Biomarkers (ID 161)
- Event: WCLC 2013
- Type: Poster Session
- Track: Biology
- Presentations: 1
- Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P1.06-049 - Analysis of Tn antigen and its relationship with clinic, histologic and biomarkers profile in patients with non-small-cell lung cancer (NSCLC). (ID 2897)
09:30 - 16:30 | Author(s): E. Osinaga
The Tn antigen (GalNAc alpha-O-Ser/Thr), a product of incomplete O-glycosylation, is expressed in about 90% of human carcinomas, but not in normal human tissues, being associated with poor prognosis in breast cancer. There is no information about the relationship between Tn antigen expression and clinical outcome of patients with lung cancer. Aim: To study the frequency of expression of the Tn antigen in a large set of surgically resected NSCLC tumor tissues, and its association with clinical, pathological and molecular characteristics including patient’s recurrence-free survival (RFS) and overall survival (OS).
We used tumor tissue microarrays containing 426 NSCLCs, including 281 adenocarcinomas (ADC) and 145 squamous cell carcinomas (SCC). We performed immunohistochemistry using the murine monoclonal antibody 83D4. The expression of the Tn antigen was quantified using a four-value intensity score (0, 1+, 2+, and 3+) and the percentage (0-100%) of tumor stained cells. The final score obtained was in the range 0-300. The patients were divided into 2 groups: those who received neoadjuvant chemotherapy (WNA) (n=67), and those without this treatment (WONA) (n=359).
We found frequent Tn antigen expression in NSCLC. ADCs expressed high levels of the Tn antigen in 72.7% of cases while in SCCs Tn antigen was found in 27.3% of cases (p<0,004). In relation to smoking, patients with positive smoking history (smokers and former smokers) presented statistically higher expression of Tn than nonsmokers, (p = 0.001). We observed a trend of the Tn antigen expression in favor of male, Caucasian, under 70 years, adjuvant treatment and stage higher than I, not statistically significant. In patients with ADC but without neoadyuvant treatment, we found a statistically significant correlation of Tn antigen expression with positive smoking history too (p = 0.001) and its expression is different according the histology pattern, showing higher value in solid histology pattern and lower in lepidic, papilar and acinar histology pattern. Using Spearman Correlation test, Tn antigen correlated significantly with EpCAM-N (n = 393, r = 0.20, p = 0.001), EpCAM-C (n = 391, r = 0.12, p = 0.01), TTF-1 (n = 250, r = -0.29 p = 0.001), mutated EGFR status (p = 0.001) and KRAS (p = 0.01) and not with EML4-ALK fusion gene (p = NS). Interestingly, in the ADC-WONA subset, the high level of Tn antigen, are significantly associated with poor prognosis in RFS (p <0.04, HR = 1.45) and strong tendency in OS (p = 0.06, HR = 1.47). In the group ADC-WNA, high level of Tn antigen was significantly associated with poor prognosis in OS (p <0.02, HR = 2.84) and no difference in RFS. Patients with SCC in both groups, with or without neoadjuvant, showed no difference in prognosis regarding Tn antigen expression.
Tn antigen is frequently expressed in NSCLC and associates with worse prognosis in patients with ADC. Our data showed a significant correlation between the Tn antigen expression and other useful molecular markers in lung cancer (EPCAM, TTF-1, EGFR and KRAS), opening a new possible candidate for targeted therapy.