Table 2

Molecular features of young colorectal cancer patients

Patient No	MSI	Immunohistochemistry		MMR germline testing	Other molecular genetic information
Patient No	MSI	MLH1	MSH2	MMR germline testing	Other molecular genetic information
*Patient No 8 is the daughter of patient No 15.
NT, not tested; MMR, mismatch repair.
MSI, microsatellite instability—H, high frequency of microsatellite instability; S, microsatellite stable.
Immunohistochemistry: I, intact; D, deficient.
1	H	I	I	Homozygous MLH1 mutation²⁰	Normal karyotype
				Exon 18 codon 687 CGG>TGG Arg287Trp
2	H	NT	NT	PMS2 mutation¹⁹
				Exon 5 codon 134,CGA→TGA Arg→stop
3	H	I	D	MSH2 mutation
				Exon 8 del codons 427–462
4	S	I	I	No mutation found (MLH1 and MSH2)	Normal karyotype
5	S	NT	NT	NT
6	S	I	I	NT
7	NT	NT	NT	NT	Kin had MSI-H and MSH2 deficient tumour, no germline mutation found
8*	NT	NT	NT	NT	Kin had MSI-H and MLH1/MSH2 immuno intact tumour, no germline mutation found
9	H	I	D	MSH2 mutation
				Exon 12 codon 636 G→C (1906G>C A636P)
10	H	D	I	MLH1 mutation
				Exon 19 codon 730 (4bp ins AACA) STOP nucl2234–2236
11	NT	NT	NT	No mutation found (MLH1 and MSH2)	Kin had MSS tumour, no germline mutation found
12	H	D	I	No mutation found (MLH1 and MSH2)	Tumour was methylated at the MLH1 promoter
13	NT	NT	NT	No mutation found (MLH1 and MSH2)
14	NT	NT	NT	MSH2 mutation
				Exon 15 codon 878 2633_2634delAG (E878fsX88)
15*	H	I	I	No mutation found (MLH1 and MSH2)
16	H	I	I	No mutation found (MLH1 and MSH2)