Table 1.

Clinical characteristics of unexplained MSH2-type Lynch syndrome patients

Diagnosis		Age at diagnosis	MSH2/MSH6 IHC	MSI testing	Germline testing	Amsterdam I criteria	Amsterdam II criteria	Bethesda criteria	PREMM 1,2,6	Inversion (%)
213	Endometrial adenocarcinoma	55	Absent	ND	MSH2-VUS L800P	Negative	Positive	Positive	27	No
314	Synchronous endometrial & ovarian adenocarcinoma	46	Absent	MSI-H	NMD	Negative	Positive	Negative	38	Yes
328	Endometrial adenocarcinoma	44	Absent	MSI-H	NMD	Negative	Negative	Negative	<5	No
370	Endometrial adenocarcinoma Mucinous cecal adenocarcinoma	41 47	Absent	MSI-H	NMD	Positive	Positive	Positive	36.90	Yes
372	Muir-Torre syndrome Stage I cecal poorly differentiated adenocarcinoma	41 47	Absent	MSI-H	NMD	Positive	Positive	Positive	65.80	Yes
381	Colon adenocarcinoma Endometrial adenocarcinoma Squamous cell kidney cancer	41 47 48	Absent	MSI-H	NMD	Positive	Positive	Positive	94	Yes
431	Stage II mucinous hepatic flexure adenocarcinoma	57	Absent	ND	NMD	Negative	Positive	Positive	29	No
474	Stage III cecal adenocarcinoma	40	Absent	ND	MSH2-VUS V163D	Positive	Positive	Positive	62	No
538	Rectal adenocarcinoma Terminal ileum adenocarcinoma	41 43	Absent	MSI-H	NMD	Positive	Positive	Positive	89.80	Yes
572	CIS in a large colonic polyp	40	Absent	ND	ND	Positive	Positive	Positive	25.20	Yes

For six of the patients, the positive inversion test results are highlighted. For two of the remaining four patients who are negative for the inversion, the VUS identified in their germline testing results is indicatd in bold. Of the remaining two unsolved cases, the negative Amsterdam and Bethesda criteria as well as low PREMM score are indicated in bold. Only one unexplained case remains

CIS Carcinoma in situ (high grade dysplasia), MTS Muir-Torre syndrome, ND not done, NMD no mutation detected, VUS variant of uncertain significance