Background
Methods
Study population, microsatellite instability analysis, dietary and lifestyle assessment
Tissue processing and DNA extraction
DNA extraction
Mutation detection
PTEN immunohistochemistry
Statistical analysis
Results
PTEN and PIK3CAmutation frequencies and PTEN expression status in colorectal adenocarcinomas and adenomas
PTEN mutations in exons 7 and 8 | |||
---|---|---|---|
Mutations in adenocarcinomas | Mutations in adenomas | Total | |
Codon 233: wildtype CGA*
| |||
TGA (Arg to Stop) | 1 | 0 | 1 |
Codon 339: wildtype CCA*
| |||
TCA (Phe to Ser) | 1 | 0 | 1 |
Poly-A tract (codons 321-323)
| |||
1 bp insertion | 1 | 0 | 1 |
Poly-A tract (codons 321-323)
| |||
1 bp deletion | 1 | 0 | 1 |
Codon 316 (1
st
base) to 323 (2
nd
base)
| |||
23 bp deletion | 1 | 0 | 1 |
Total
| 5 | 0 |
5
|
PIK3CA
mutations in exons 8, 9 and 20
| |||
Mutations in adenocarcinomas | Mutations in adenomas | Total | |
Codon 542: wildtype GAA
| |||
GTA (Glu to Val) | 1 | 0 | 1 |
AAA (Glu to Lys) | 2 | 0 | 2 |
Codon 545: wildtype GAG
| |||
AAG (Glu to Lys) | 2 | 1 | 3 |
Codon 546: wildtype CAG
| |||
AAG (Gln to Lys) | 2 | 0 | 2 |
CGG (Gln to Arg) | 1 | 0 | 1 |
Codon 1046: wildtype CAT
| |||
CGT (His to Arg) | 5 | 0 | 5 |
Total
| 13 | 1 |
14
|
Lifestyle and clinicopathological factors in relation to PTEN expression and PIK3CAmutation
PTEN expression status |
PIK3CA mutation status | |||||
---|---|---|---|---|---|---|
Characteristic | Positive | Negative |
P
‡
| Wildtype | Mutant |
P
‡
|
n = 112†
|
n = 60†
|
n = 172†
|
n = 13†
| |||
Sex
| ||||||
Male | 48.2 (54) | 46.7 (28) | 52.0 (90) | 23.1 (3) | ||
Female | 51.8 (58) | 53.3 (32) | 0.85 | 48.0 (83) | 76.9 (10) |
0.04
|
Age at diagnosis (years) | 71.0 (7.5) | 70.0 (8.0) | 0.43* | 70.3 (7.7) | 73.3 (5.6) | 0.17* |
Tumour location
| ||||||
Proximal colonic | 34.0 (35) | 42.9 (24) | 34.4 (55) | 53.8 (7) |
(FET)
| |
Distal colonic/Rectal | 66.0 (68) | 57.1 (32) | 0.27 | 65.6 (105) | 46.2 (6) | 0.23 |
Differentiation
| ||||||
Well/Moderate | 86.9 (86) | 87.0 (47) | 84.9 (129) | 92.3 (12) |
(FET)
| |
Poor | 13.1 (15) | 13.0 (7.0) | 0.98 | 15.1 (23) | 7.7 (1) | 0.69 |
Dukes' Stage
| ||||||
A/B | 53.6 (52) | 55.8 (29) | 54.4 (80) | 61.5 (8) | ||
C/D | 46.4 (45) | 44.2 (23) | 0.80 | 45.6 (67) | 38.5 (5) | 0.62 |
MSI status
| ||||||
MSS | 83.0 (88) | 83.3 (45) | 84.6 (126) | 63.6 (7) |
(FET)
| |
MSI | 17.0 (18) | 16.7 (9) | 0.96 | 15.4 (23) | 36.4 (4) | 0.09 |
BMI (kg/m2) | 27.3 (4.1) | 26.6 (4.4) | 0.36* | 27.3 (4.3) | 25.7 (4.4) | 0.20* |
Alcohol consumption
| 9.7 (16) | 6.6 (9.7) | 0.17* | 9.5 (15.0) | 5.4 (10) | 0.34* |
Smoking status
| ||||||
Current | 12.0 (13) | 8.3 (5) | 11.2 (19) | 0.0 (0) | ||
Former | 46.3 (50) | 45.0 (27) | 45.6 (77) | 58.3 (7) | ||
Never | 41.7 (45) | 46.7 (28) | 0.69 | 43.2 (73) | 41.7 (5) | 0.42 |
Physical activity
| ||||||
Low | 64.3 (72) | 70.0 (42) | 65.7 (113) | 84.6 (11) |
(FET)
| |
High | 35.7 (40) | 30.0 (18) | 0.45 | 34.3 (59) | 15.4 (2) | 0.23 |
HRT status
| ||||||
Current | 10.3 (6) | 6.5 (2) | 9.8 (8) | 0.0 (0) | ||
Former | 17.2 (10) | 16.1 (5) | 17.1 (14) | 20.0 (2) | ||
Never | 72.4 (42) | 77.4 (24) | 0.81 | 73.2 (60) | 80.0 (8) | 0.58 |
LDL cholesterol (mmol/l) | 4.28 (1.2) | 3.90 (1.1) |
0.05*
| 4.12 (1.1) | 4.30 (1.0) | 0.61* |
HDL cholesterol (mmol/l) | 1.31 (0.4) | 1.30 (0.4) | 0.96* | 1.30 (0.4) | 1.29 (0.4) | 0.93* |
Triglyceride (mmol/l) | 1.99 (0.8) | 2.25 (1.6) | 0.17* | 2.09 (1.1) | 2.11 (1.5) | 0.95* |
Plasma vitamin C (μmol/l) | 50.3 (18) | 53.3 (33) | 0.47* | 51.2 (24) | 54.1 (19) | 0.71* |
Dietary factors and PTEN expression in CRC
PTEN expression status | |||
---|---|---|---|
Dietary factor | Positive n= 112 | Negative n= 60 |
P
‡
|
Meat
| |||
Red Meat (g/d) | 36 (27.1) | 39 (30.3) | 0.56 |
Processed Meat (g/d) | 26 (19.2) | 24 (19.5) | 0.60 |
Red + Processed Meat (g/d) | 62 (37.3) | 63 (34.1) | 0.86 |
White Meat (g/d) | 19 (18.7) | 21 (18.2) | 0.49 |
White Fish (g/d) | 17 (19.5) | 16 (14.0) | 0.59 |
Fatty Fish (g/d) | 12 (21.8) | 10 (13.7) | 0.38 |
Fruit and vegetables
| |||
Fruit (g/d) | 177 (144.1) | 163 (125.0) | 0.53 |
Vegetables (g/d) | 135 (73.1) | 140 (60.0) | 0.63 |
Fat
| |||
Total Fat (g/d) | 70 (22.9) | 73 (22.2) | 0.31 |
PUFA (g/d) | 13 (5.4) | 14 (5.2) | 0.50 |
MUFA (g/d) | 24 (8.1) | 26 (7.9) | 0.12 |
SFA (g/d) | 27 (10.3) | 28 (9.8) | 0.53 |
Vitamins
| |||
B2[riboflavin] (mg/d) | 2 (0.6) | 2 (0.6) | 0.91 |
B3[niacin] (mg/d) | 18 (5.4) | 18 (6.3) | 0.56 |
B6[pyroxidine] (μg/d) | 2 (0.6) | 2 (0.6) | 0.76 |
B9[folate] (μg/d) | 257 (73.3) | 260 (69.2) | 0.79 |
B12 (μg/d) | 6 (5.6) | 5 (3.7) | 0.29 |
C (mg/d) | 85 (49.0) | 84 (44.8) | 0.85 |
D (μg/d) | 3 (2.2) | 3 (2.2) | 0.99 |
Fibre and Macronutrients
| |||
Total Energy (MJ/d) | 8 (2.1) | 8.0 (1.9) | 0.38 |
Carbohydrate (g/d) | 230 (65.4) | 245 (67.9) | 0.17 |
Protein (g/d) | 70 (15.1) | 70 (14.3) | 0.97 |
NSP (g/d) | 14 (5.7) | 15 (5.3) | 0.44 |
Calcium (mg/d) | 773 (239.2) | 795 (220.1) | 0.55 |
PTEN expression negative cancers stratified by Dukes' stage and tumour location
PTEN expression negative colorectal adenocarcinomas | ||||||
---|---|---|---|---|---|---|
Characteristic | Dukes' stage A/B
n= 29†
| Dukes' stage C/D
n= 23†
|
P
‡
| Proximal colonic
n= 24†
| Distal colonic/Rectal
n= 32†
|
P
‡
|
Sex
| ||||||
Male | 58.6 (17) | 39.1 (9) | 41.7 (10) | 46.9 (15) | ||
Female | 41.4 (12) | 60.9 (14) | 0.16 | 58.3 (14) | 53.1 (17) | 0.70 |
Age at diagnosis (years) | 70.3 (8.14) | 69.0 (8.67) | 0.56 | 71.0 (7.31) | 69.1 (8.77) | 0.41 |
Tumour location
| ||||||
Proximal colonic | 37.5 (9) | 72.0 (18) |
a
|
a
| ||
Distal colonic/Rectal | 62.5 (15) | 28.0 (7) |
0.02
|
a
|
a
|
a
|
Differentiation
| ||||||
Well/Moderate | 92.6 (25) | 78.3 (18) |
(FET)
| 69.6 (16) | 100.0 (28) |
(FET)
|
Poor | 7.4 (2) | 21.7 (5) | 0.23 | 30.4 (7) | 0.0 (0) |
<0.01
|
Dukes' Stage
| ||||||
A/B |
a
|
a
| 37.5 (9) | 72.0 (18) | ||
C/D |
a
|
a
|
a
| 62.5 (15) | 28.0 (7) |
0.02
|
MSI status
| ||||||
MSS | 81.5 (22) | 84.2 (16) |
(FET)
| 72.7 (16) | 89.7 (26) |
(FET)
|
MSI | 18.5 (5) | 15.8 (3) | 1.00 | 27.3 (6) | 10.3 (3) | 0.15 |
BMI (kg/m2) | 26.2 (3.60) | 26.4 (4.77) | 0.85 | 26.5 (4.71) | 26.4 (3.64) | 0.93 |
Alcohol consumption
| 6.6 (11.1) | 6.5 (7.8) | 0.97 | 4.0 (5.7) | 8.0 (10.8) | 0.11 |
Smoking status
| ||||||
Current | 13.8 (4) | 4.3 (1) | 8.3 (2) | 9.4 (3) | ||
Former | 41.4 (12) | 52.2 (12) | 54.2 (13) | 40.6 (13) | ||
Never | 44.8 (13) | 43.5 (10) | 0.47 | 37.5 (9) | 50.0 (16) | 0.60 |
Physical activity
| ||||||
Low | 69.0 (20) | 65.2 (15) | 58.3 (14) | 78.1 (25) | ||
High | 31.0 (9) | 34.8 (8) | 0.78 | 41.7 (10) | 21.9 (7) | 0.11 |
LDL cholesterol (mmol/l) | 3.70 (1.05) | 3.94 (1.11) | 0.45 | 3.82 (1.17) | 3.97 (0.98) | 0.62 |
HDL cholesterol (mmol/l) | 1.29 (0.39) | 1.33 (0.50) | 0.76 | 1.30 (0.51) | 1.34 (0.36) | 0.69 |
Triglyceride (mmol/l) | 1.90 (1.21) | 2.75 (1.95) |
0.06
| 2.48 (1.61) | 1.97 (1.35) | 0.21 |
Plasma vitamin C (μmol/l) | 46.6 (18.9) | 52.7 (23.1) | 0.32 | 48.1 (19.5) | 56.6 (40.1) | 0.37 |
Mutations in PTEN and PIK3CA and loss of PTEN expression in relation to BRAF and K-RASmutations
BRAF mutant |
BRAF wildtype | ||
K-RAS mutant |
3.4 (1)
|
25.5 (40)
| |
K-RAS wildtype |
96.6 (28)
|
74.5 (117)
|
p = 0.009
|
BRAF mutant |
BRAF wildtype | ||
PTEN mutant |
13.8 (4)
|
0.0 (0)
| (FET) |
PTEN wildtype |
86.2 (25)
|
100.0 (157)
|
p < 0.001
|
BRAF mutant |
BRAF wildtype | ||
PTEN expression negative | 37.0 (10) | 34.5 (50) | |
PTEN expression positive | 63.0 (17) | 65.5 (95) | p = 0.80 |
BRAF mutant |
BRAF wildtype | ||
PIK3CA mutant | 13.8 (4) | 5.7 (9) | (FET) |
PIK3CA wildtype | 86.2 (25) | 94.3 (148) | p = 0.12 |
K-RAS mutant |
K-RAS wildtype | ||
PIK3CA mutant | 7.3 (3) | 6.9 (10) | (FET) |
PIK3CA wildtype | 92.7 (38) | 93.1 (135) | p = 1.00 |
K-RAS mutant |
K-RAS wildtype | ||
PTEN mutant | 0.0 (0) | 2.8 (4) | (FET) |
PTEN wildtype | 100.0 (41) | 97.2 (141) | p = 0.58 |
K-RAS mutant |
K-RAS wildtype | ||
PTEN expression negative | 41.7 (15) | 33.1 (45) | |
PTEN expression positive | 58.3 (21) | 66.9 (91) | p = 0.34 |
PIK3CA mutant |
PIK3CA wildtype | ||
PTEN expression negative | 23.1 (3) | 35.8 (57) | (FET) |
PTEN expression positive | 76.9 (10) | 64.2 (102) | p = 0.55 |
PIK3CA mutant |
PIK3CA wildtype | ||
PTEN mutant | 7.7 (1) | 1.7 (3) | (FET) |
PTEN wildtype | 92.3 (12) | 98.3 (170) | p = 0.25 |