Table 4 Associations of genetic polymorphisms in GSTT1, GSTM1, GSTP1 and TYMS with outcome and toxicity

From: Chemoradiotherapy with capecitabine for locally advanced anal carcinoma: an alternative treatment option

 

Clinical response

Overall toxicity

Polymorphism

PR

CR

P-value a

Grade 0–2

Grade 3–4

P-value a

GSTT1 (deletion)

Not NULL

7 (9%)

68 (91%)

0.686

55 (72%)

21 (28%)

0.065

NULL

3 (14%)

18 (86%)

 

10 (48%)

11 (52%)

 

GSTM1 (deletion)

Not NULL

4 (11%)

34 (89%)

1.000

26 (68%)

12 (32%)

0.827

NULL

6 (10%)

52 (90%)

 

38 (66%)

20 (35%)

 

GSTP1 313A>G

AA

5 (12%)

38 (88%)

0.749

33 (77%)

10 (23%)

0.124

AG or GG

5 (9%)

48 (91%)

 

32 (60%)

21 (40%)

 

TYMS 3’-UTR 6-bp ins/del

Ins/Ins

6 (15%)

33 (85%)

0.307

25 (64%)

14 (36%)

0.657

Ins/Del or Del/Del

4 (7%)

53 (93%)

 

40 (70%)

17 (30%)

 

TYMS 5’-UTR VNTR b

High expressor

4 (12%)

30 (88%)

0.739

28 (82%)

6 (18%)

0.025

Low expressor

6 (10%)

56 (90%)

 

37 (60%)

25 (40%)

 
  1. Abbreviations: CR=complete response; GSTM1=glutathione S-transferase mu; GSTP1=glutathione S-transferase pi; GSTT1=glutathione S-transferase theta; TYMS=thymidylate synthase; PR=partial response; VNTR=variable number of 28-bp tandem repeats.
  2. aFisher’s exact test (two-sided).
  3. bLow TYMS expression genotypes are (*2/*2, *2/*3C and *3C/*3C) and high TYMS expression genotypes (*2/*3G, *3C/*3G or *3G/*3G).