[2142] Targeted Mutation Analysis of Endometrial Cancer Using a Custom Sequenom® MassARRAY Panel: A Proof-of-Principle Study

Sarah E Kerr, Leonard M Holtegaard, Lisa M Peterson, Fabiola Medeiros, Andrea Mariani, W Edward Highsmith, Benjamin R Kipp, Kevin C Halling. Mayo Clinic, Rochester, MN

Background: Somatic mutation analysis has become a useful tool in selecting personalized therapy for solid tumors, and may have uses for cancer screening and prognosis. As the number of gene targets increases, next-generation sequencing has been proposed as the ultimate solution to mutation detection, however, highly multiplexed targeted mutation analysis is currently more cost- and time-effective. This study explores the use of a highly multiplexed mutation detection panel designed for endometrial cancer using the Sequenom MassARRAY platform.
Design: DNA was extracted from fresh frozen (n = 75) or formalin fixed, paraffin embedded (n = 26) endometrial cancer unstained sections. Samples were subjected to a 16-well multiplexed assay targeting 19 genes and 182 mutations using PCR followed by single base extension chemistry and matrix assisted laser desorption/ionization time-of-flight detection.
Results: Mutations were detected in PTEN (45), PIK3CA (31), KRAS (15), TP53 (15), FGFR2 (7), FBXW7 (4), CTNNB1 (4), NRAS (2), HRAS (1), CDKN2A (1), and AKT1 (1). At least one mutation was detected in 76% of the cases, and 91% of grade 1 or 2 endometrioid adenocarcinoma. The median number of mutations detected per case was 1 (range 0-4). The most frequently mutated genes are shown by histologic type in Table 1.

N Cases With Mutation (%)

Histology (n)	Any mutation	PTEN*	PIK3CA*	KRAS	TP53	FGFR2	FBXW7
Endometrioid (57)	49 (86)	28 (49)	21 (37)	11 (19)	4 (7)	6 (11)	1 (2)
Grade 1 (25)	23 (92)	15 (60)	10 (40)	6 (24)	0 (0)	1 (4)	1 (4)
Grade 2 (10)	9 (90)	7 (70)	4 (40)	1 (10)	0 (0)	3 (30)	0 (0)
Grade 3 (22)	17 (77)	6 (27)	7 (32)	4 (18)	4 (18)	2 (9)	0 (0)
Non-endometrioid (44)	28 (64)	6 (14)	8 (18)	4 (9)	11 (25)	1 (2)	3 (7)
Carcinosarcoma (20)	12 (60)	2 (10)	2 (10)	2 (10)	5 (25)	1 (5)	0 (0)
Serous (16)	12 (75)	2 (13)	5 (31)	1 (6)	4 (25)	0 (0)	3 (19)
Clear cell (6)	3 (50)	1 (17)	1 (17)	1 (17)	1 (17)	0 (0)	0 (0)
Mixed (2)	1 (50)	1 (50)	0 (0)	0 (0)	1 (50)	0 (0)	0 (0)
Total cases (101)	77 (76)	34 (34)	29 (29)	15 (15)	15 (15)	7 (7)	4 (4)

*11 cases had 2 PTEN mutations and 2 cases had 2 PIK3CA mutations.


Conclusions: This study reveals the spectrum and frequency of mutations observed in commonly mutated genes in endometrial cancer. Highly multiplexed assays may be a practical bridge to next generation sequencing for mutation detection. While several of the oncogenes tested have companion targeted therapies in clinical trials, the high mutation detection rate for endometrioid adenocarcinoma may make this approach useful for early detection screening methodologies. Further exploration for oncogenes that are commonly altered in high-grade cancer types is needed.
Category: Techniques

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 311, Monday Morning