Table 5.

Summary of patients with tissue testing results concerning for Lynch Syndrome with corresponding germline results, if available

Study #	Age at Diagnosis	Family History	MSI	IHC Result	Germline Testing
1023	68	Brother CRC1 at 55 yrs	MSI-H	Loss of PMS2	Insurance declined testing
1050	65	Sister CRC at 53; P2 aunt X 2 ovarian or endometrial cancer; P uncle CRC	MSI-H	Loss of MSH6	MSH6 c.3238_3239delCT, p.L1080VfsX12
1051	49	P aunt CRC 50s; p nephew CRC 50s; sister Endometrial cancer at 49	MSI- H	Loss of PMS2	PMS2 deletion of exon 10
1060	75	Sister with cancer, type unknown to patient	MSI-H	Loss of MSH6	Negative for MSH2 or MSH6
1068	62	None	MSS	Loss of MSH6	MSH6 c.2805_2806delTG, p.D396LfsX2
1088	47	P uncle and father with CRC; P aunt with ovarian cancer	MSI- H	Loss of MLH1/PMS2 No MLH1 methylation	MLH1 deletion of exons 2–3
1126	69	None	MSI-H	Loss PMS2	Negative for MLH1 or PMS2
1131	59	Mother gastric cancer at 71	MSI-H	Loss of MLH1/PMS2 No MLH1 methylation	Insurance declined testing
1147	86	None	MSI-H	Intact staining of all four proteins with MLH1 methylation	Patient declined genetic counseling
1165	40	PGM CRC60s, P Aunt CRC 40s, P Aunt CRC 60s, P Cousin CRC at 28	MSI- H	Loss of MLH1/PMS2 No MLH1 methylation	MLH1 C.298C>T, p.R100
1204	42	Mother CRC 60s, MGM CRC 60s, M3 Uncle CRC 50s, Maternal uncle CRC 50s	MSI-H	Loss of MLH1/PMS2 No MLH1 methylation	MLH1 deletion in exons 16– 19
1206	54	None	MSI-H	Loss of MSH2/MSH6	Negative for MSH2
1212	64	None	MSI- H	Loss of MSH2/MSH6	Patient declined testing
1181	79	Sister with CRC at 65; sister with gyn cancer in 40s	MSI- H	Loss of MLH1/PMS2 MLH1 methylation not performed - insurance declined	MLH1 VUS4 IVS12-10T>G
11595	23	Personal history of CRC at 17	Not performed	Not performed	PMS2

¹CRC, colorectal cancer

²P, paternal

³M, maternal

⁴VUS – Variant of unknown significance; this patient had a strong family history of Lynch-associated cancers and a personal history of colorectal cancer.

⁵Young patient with history of colon cancer prior to diagnosis of endometrial cancer. Constitutional mismatch repair deficiency was suspected by the genetics counselors, so no tissue testing was ordered. Genetic testing was performed at the time of colon cancer diagnosis, and documentation confirms a PMS2 mutation but specific mutation is not available.