Role of CEA, PLUNC and CK19 mRNA expression in lymph nodes from resected stage I non-small cell lung cancer (NSCLC) patients (p) as markers of occult micrometastasis. A pilot study

Abstract

9654 Background: 5-year survival for p with surgically resected stage IA-IB (NSCLC) is 70 and 38%. Recurrence of the disease is probably due to undetected systemic occult micrometastases (OM) at the time of initial diagnosis in the histopathologic analysis.The detection of OM would require a more sensitive and specific technique and would be of the greatest interest to define a high risk population and select p for postoperative adjuvant treatments. Objective: to assess the role of CEA, PLUNK and CK19 mRNA expression in pathological negative lymph nodes (LN) from resected stage I NSCLC p as markers of OM and correlate the results with relapse. Methods: paired tumour and histological negative LN (n=84) from 10 p were analyzed for the presence of CEA, CK19 and PLUNC mRNA expression using quantitative real-time PCR Q-PCR. RNA was extracted; GADPH was used as an endogenous control.Samples were also analyzed by immunohistochemistry for LN staging. Results: 10 NSCLC p;7 males;age range:47–77;5 adenoca, 3 squamous cell ca and 2 undiff tumours. CK19 and PLUNC were found to be expressed in tumour tissue of all p.CEA did not express in one of the squamous cell ca. tissues. In the 84 pathological negative LN, 23, 8% (20/84) were positive for CEA, 20%(17/84) for PLUNC,100%(84/84) for CK19 mRNA expression. Most LN positive for CEA were positive for PLUNC as well. The expression pattern were very similar for both markers in all 10 p analyzed.6/10 p showed positive lymph nodes and 4/10 were negatives.1/10 p relapsed after 11 mo of surgery and died after 18 mo. P had detectable levels of CEA and PLUNC mRNA in LN assessed by Q-PCR. The 9 p that did not relapse, 4 had no detectable LN expression levels of these markers and 5 had detectable LN expression levels (median follow-up of 12,5 mo; range 4–18 mo). Conclusions: CK19 has shown to be non specific tumoral marker since it were found to be expressed in all LN tested. But CEA and PLUNC have shown to be specific markers of OM.This fact could be of prognostic relevance and maybe a tool for select high-risk patients considered for adjuvant therapies.50 p are being assessed to corroborate this finding. Final data will be presented. No significant financial relationships to disclose.