Table 3.

Characteristics and outcomes of patients with abnormal immunohistochemistry screening

Case	Age at CRC diagnosis	Gender	Race	SER stage	CRC location	Modified Amsterdam or Bethesda guidelines met?	Absent MMR protein	Genetic work-up outcome	Diagnosis
A	40	M	Hispanic	3	Ascending	Amsterdam	MLH1/PMS2	MLH1 mutation (exon 12, c1168,_1169insG)	Definite Lynch syndrome (LS)
B	40	M	White	1	Ascending	Bethesda	MSH6	MSH6 mutation (exon 4, 2731C>T)	Definite LS
C	52	M	Black	1	Transverse	Amsterdam	MSH6	MSH6 mutation (exon 4 1705_1706del TT)	Definite LS
D	53	M	White	2	Rectum	Bethesda	MSH2	MSH2 mutation (1165C>T)	Definite LS
E	57	M	Hispanic	1	Cecum	Bethesda	MSH2/MSH6	No-show for genetic counseling	Incomplete work-up
F	49	F	Black	4	Rectum	Bethesda	MLH1/PMS2	Previously diagnosed with Li Fraumeni syndrome, no additional genetic work-up pursued	No LS
G	54	M	Hispanic	1	Transverse	Bethesda	MLH1/PMS2	Normal MLH1/PMS2 testinga with positive BRAF mutation	No LS
H	61	F	Hispanic	4	Cecum	Bethesda	MLH1/PMS2	Normal MLH1/PMS2 testinga with positive BRAF mutation	No LS
I	53	M	White	4	Rectum	Bethesda	MSH2/MSH6	Normal MSH2, MSH6, and EPCAM testinga	Probable LS
J	55	M	White	2	Descending	Bethesda	MSH2/MSH6	Normal MSH2, MSH6, and EPCAM testinga	Probable LS
K	63	M	Hispanic	4	Cecum	Neither	MLH1/PMS2	Normal MLH1/PMS2 testinga with negative BRAF and MLH1 methylation analyses	Probable LS
L	65	F	Black	1	Hepatic flexure	Neither	MSH2/MSH6	Normal MSH2, MSH6, and EPCAM testinga	Probable LS

CRC, colorectal cancer; F, female; M, male; MMR, mismatch repair; SEER, Surveillance Epidemiology and End Results.

^aSee Materials and Methods for details on genetic testing approaches.