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C. Leduc
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P3.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 235)
- Event: WCLC 2015
- Type: Poster
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:
- Coordinates: 9/09/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P3.04-092 - HNF4α Is a Marker for Invasive Mucinous Adenocarcinoma (IMA) and a Prognostic Factor in Stage I Lung Adenocarcinoma (LADC) (ID 3066)
09:30 - 09:30 | Author(s): C. Leduc
- Abstract
Background:
According to the 2015 WHO classification, invasive LADC with prominent apical intra-cytoplasmic mucin and small basally oriented nuclei, formerly referred to as mucinous bronchioloalveolar carcinoma, is classified as IMA. Hepatocyte nuclear factor 4 alpha (HNF4α) is a recently recognized marker for IMA although it is also infrequently positive for other subtypes of LADC. However, the prognostic significance of HNF4α is not known. We investigated the frequency of HNF4α expression in IMA as well as non-IMA subtypes, and the prognostic significance of HNF4α in Stage I LADC.
Methods:
Slides from patients with therapy-naive, surgically resected solitary stage I LADC (1995-2009) were subtyped according to the 2015 WHO classification. Tissue microarrays were constructed from each tumor (n=793), and stained for HNF4α. HNF4α expression intensity (0-3) and distribution (1, 1%-50%; 2, 51%-100%) were summed into a total score (0-5) and dichotomized as negative (score <2) or positive (score ≥2). Comparisons were made with TTF-1 expression. Recurrence-free probability (RFP) was estimated using the Kaplan-Meier method, and multivariate analyses were performed using the Cox proportional hazards model.
Results:
32 cases were identified as IMA. Of all LADC, HNF4α was positive in 68 cases (9%) including72% (n = 23) of IMA, 6% (n = 45) of tumors with non-IMA subtypes (P < 0.001). Among non-IMA subtypes, HNF4α was positive in 6% of lepidic, 4% of papillary, 2% of micropapillary, 7% of solid, and 29% of colloid tumors. HNF4α was positive in 12% of KRAS mutant tumors while it was negative in all EGFR mutant tumors (P < 0.001). HNF4α was more frequently positive in TTF-1 negative tumors (40%) than TTF-1 positive tumors (5%; P < 0.001). The RFP for patients with HNF4α-positive tumors was significantly lower than that for patients with HNF4α-negative tumors (P = 0.002) in the entire cohort. This finding was confirmed in subgroup analysis of patients with non-IMA subtypes (P = 0.009). In multivariate analysis, HNF4α was an independent prognostic factor for recurrence (HR=1.61, 95%CI =1.27-2.02, p<0.001).
Conclusion:
HNF4α expression was significantly associated with IMA histology, negative EGFR mutation status, and TTF-1 negativity. Furthermore HNF4α was also expressed infrequently in non-IMA subtypes, however in these patients it was a significant prognostic factor.
