To the editor:

Peripheral T-cell lymphomas (PTCLs) are a group with poor outcome and nonspecific therapeutic regimens. Recently, Palomero et al1  and Sakata-Yanagimoto et al2  identified a recurrent heterozygous mutation in the RHOA small GTPase gene encoding a p.Gly17Val alteration (G17V) that leads to inhibition of the ρ-signaling pathway. Because the RHOA/ρ-kinase pathway plays a pivotal role in many cellular functions, we wanted to establish whether the G17V mutation of the RHOA gene (RHOA-G17V) has any biological relevance in nodal PTCL (n-PTCL).

Twenty-six frozen n-PTCL-samples (13 peripheral T-cell lymphomas not specified [PTCL-NOSs], 11 angioimmunoblastic T-cell lymphomas [AITLs], and 2 anaplastic large cell lymphomas) were hybridized on a whole-human-genome oligo microarray and analyzed for the presence of the RHOA-G17V using a specific qBiomarker somatic-mutation PCR assay (SABiosciences). Expression profile data were analyzed with gene set enrichment analysis software. RHOA-G17V was found in 6 AITLs and 3 PTCL-NOSs (34.6% of cases). Thirty-two gene sets were overrepresented in the mutated subgroup of tumors. Of particular significance were the pathways related to the follicular helper CD4 T-cell and AITL signature. Moreover, other pathways of great relevance to PTCL pathogenesis, such as p38 mitogen-activated protein kinase, phosphatidylinositol 3-kinase, KRAS, the alternative nuclear factor κB (NF-κB) pathway, and the RAC1 pathway, were significantly associated with the presence of the RHOA-G17V (see supplemental Table 1 available at the Blood Web site).

The presence of RHOA-G17V was further analyzed by the previously described method in an independent consecutive series of 136 paraffin-embedded n-PTCL samples. Positive results were confirmed by Sanger sequencing of the mutated region. A total of 26.4% (32/121) of the cases carried RHOA-G17V. A total of 34.2% (25/73) of cases were AITL; 14.6% (7/48) were PTCL-NOS (P = .016), 3 of which had AITL-like features. The lower percentage of mutated cases than previously reported,1,2  especially in AITLs, may have been due to the lower sensitivity of our assay and the paucity of tumoral cells in some AITL cases.

Immunohistochemical studies using tissue microarrays revealed a positivity for programmed cell death 1 (PD-1),3  phospho-extracellular signal-regulated kinase (p-ERK), p50, and p52 in 48.5% (66/136), 32.1% (41/136), 72.1% (98/136), and 59.6% (81/136) of patients, respectively. The presence of PD-1, nuclear p-ERK, or p52 expression was significantly positively correlated with the presence of RHOA-G17V (P = .024, 0.002, and 0.042, respectively).

There is a relationship between RHOA and Rac1 in which a high level of Rac activity leads to a reduction in that of ρ, and vice versa.4  Rac1 activity also activates multiple downstream effectors, including the NF-κB, p38 mitogen-activated protein kinase, and mitogen-activated protein kinase kinase/extracellular signal-regulated kinase pathways.5,6  These findings are consistent with gene set enrichment analysis results, and some of them were validated by immunohistochemistry in an independent series of patients. However, explanations involving other biological mechanisms cannot be ruled out.7 

Although standard prognostic indices for this series (International Prognostic Index and Prognostic Index for PTCL-u) identified prognostic subgroup of patients (both indices, P < .001), the mutational status of the RHOA gene did not, either in the total group of all patients or after histologic subclassification (AITL vs PTCL-NOS) (Table 1 and supplemental Tables 2-3 available on the Blood Web site.).

Table 1

Univariate analysis of the clinical and molecular parameters and the mutational status of the RHOA gene in the cohort of 121 patients with PTCLs

RHOATotal casesWTMUTP
DX 121/121   .016 
 AITL 48/73 (65.8%) 25/73 (34.2%) 
 PTCL-NOS 41/48 (85.4%) 7/48 (14.6%) 
p-ERK 121/121   .002 
 Negative 70/86 (81.4%) 16/86 (18.6%) 
 Positive 19/35 (54.3%) 16/35 (45.7%) 
p50 118/121   .166 
 Negative 25/30 (83.8%) 5/30 (16.7%) 
 Positive 62/88 (70.5%) 26/88 (29.5%) 
p52 117/121   .042 
 Negative 34/40 (85%) 6/40 (15%) 
 Positive 52/77 (67.5%) 25/77 (32.5%) 
NF-κB 119/121   .068 
 None 16/18 (88.9%) 2/18 (11.1%) 
 p50 or p52 30/37 (81.1%) 7/37 (18.9%) 
 Both 42/64 (65.6%) 22/64 (34.4%) 
PD-1 88/121   .024 
 Negative 24/27 (88.9%) 3/27 (11.1%) 
 Positive 40/61 (65.6%) 21/61 (34.4%) 
Sex 117/121   .064 
 Male 47/69 (68.1%) 22/69 (31.9%) 
 Female 40/48 (83.3%) 4/48 (16.7%) 
Age at diagnosis 114/121   .453 
 <60 y 33/42 (78.6%) 9/42 (21.4%) 
 ≥60 y 52/72 (72.2%) 20/72 (27.8%) 
IPI 106/121   .560 
 Low risk 26/32 (81.2%) 6/32 (18.8%) 
 Low-intermediate risk 18/27 (66.7%) 9/27 (33.3%) 
 High-intermediate risk 19/26 (73.1%) 7/26 (26.9%) 
 High risk 14/21 (66.7%) 7/21 (33.3%) 
PIT 94/121   .962 
 Low risk 10/14 (71.4%) 4/14 (28.6%) 
 Low-intermediate risk 26/35 (74.3%) 9/35 (25.7%) 
 High-intermediate risk 15/22 (68.2%) 7/22 (31.8%) 
 High risk 16/23 (69.6%) 7/23 (30.4%) 
ECOG 102/121   .479 
 <1 53/72 (73.6%) 19/72 (26.4%) 
 ≥1 20/30 (66.7%) 10/30 (33.3%) 
Treatment 106/121   .068 
 CHOP/CHOP-like 61/76 (80.3%) 15/76 (19.7%) 
 Others 19/30 (63.3%) 11/30 (36.7%) 
Response 96/121   .446 
 CR 44/61 (72.1%) 17/61 (27.9%) 
 PR 13/15 (86.7%) 2/15 (13.3%) 
 No response 16/20 (80%) 4/20 (20%) 
Recurrence 94/121   .660 
 No 50/66 (75.8%) 16/66 (24.2%) 
 Yes 20/28 (71.4%) 8/28 (28.6%) 
State of the patient 112/121   .615 
 Dead 50/69 (72.5%) 19/69 (27.5%) 
 Alive 33/43 (76.7%) 10/43 (23.3%) 
RHOATotal casesWTMUTP
DX 121/121   .016 
 AITL 48/73 (65.8%) 25/73 (34.2%) 
 PTCL-NOS 41/48 (85.4%) 7/48 (14.6%) 
p-ERK 121/121   .002 
 Negative 70/86 (81.4%) 16/86 (18.6%) 
 Positive 19/35 (54.3%) 16/35 (45.7%) 
p50 118/121   .166 
 Negative 25/30 (83.8%) 5/30 (16.7%) 
 Positive 62/88 (70.5%) 26/88 (29.5%) 
p52 117/121   .042 
 Negative 34/40 (85%) 6/40 (15%) 
 Positive 52/77 (67.5%) 25/77 (32.5%) 
NF-κB 119/121   .068 
 None 16/18 (88.9%) 2/18 (11.1%) 
 p50 or p52 30/37 (81.1%) 7/37 (18.9%) 
 Both 42/64 (65.6%) 22/64 (34.4%) 
PD-1 88/121   .024 
 Negative 24/27 (88.9%) 3/27 (11.1%) 
 Positive 40/61 (65.6%) 21/61 (34.4%) 
Sex 117/121   .064 
 Male 47/69 (68.1%) 22/69 (31.9%) 
 Female 40/48 (83.3%) 4/48 (16.7%) 
Age at diagnosis 114/121   .453 
 <60 y 33/42 (78.6%) 9/42 (21.4%) 
 ≥60 y 52/72 (72.2%) 20/72 (27.8%) 
IPI 106/121   .560 
 Low risk 26/32 (81.2%) 6/32 (18.8%) 
 Low-intermediate risk 18/27 (66.7%) 9/27 (33.3%) 
 High-intermediate risk 19/26 (73.1%) 7/26 (26.9%) 
 High risk 14/21 (66.7%) 7/21 (33.3%) 
PIT 94/121   .962 
 Low risk 10/14 (71.4%) 4/14 (28.6%) 
 Low-intermediate risk 26/35 (74.3%) 9/35 (25.7%) 
 High-intermediate risk 15/22 (68.2%) 7/22 (31.8%) 
 High risk 16/23 (69.6%) 7/23 (30.4%) 
ECOG 102/121   .479 
 <1 53/72 (73.6%) 19/72 (26.4%) 
 ≥1 20/30 (66.7%) 10/30 (33.3%) 
Treatment 106/121   .068 
 CHOP/CHOP-like 61/76 (80.3%) 15/76 (19.7%) 
 Others 19/30 (63.3%) 11/30 (36.7%) 
Response 96/121   .446 
 CR 44/61 (72.1%) 17/61 (27.9%) 
 PR 13/15 (86.7%) 2/15 (13.3%) 
 No response 16/20 (80%) 4/20 (20%) 
Recurrence 94/121   .660 
 No 50/66 (75.8%) 16/66 (24.2%) 
 Yes 20/28 (71.4%) 8/28 (28.6%) 
State of the patient 112/121   .615 
 Dead 50/69 (72.5%) 19/69 (27.5%) 
 Alive 33/43 (76.7%) 10/43 (23.3%) 

CHOP, cyclophosphamide, vincristine, doxorubicin, prednisone; CR, total response; DX, diagnosis; ECOG, Eastern Cooperative Oncology Group; IPI, International Prognostic Index; MUT, mutated; PIT, Prognostic Index for PTCL-u; PR, partial response; WT, wild type.

We and other researchers have previously reported the usefulness of NF-κB, phosphatidylinositol 3-kinase/AKT, and extracellular signal-regulated kinase pathway inhibitors for treating PTCL patients.8,9  The findings presented here suggest that RHOA-G17V could identify patients who are sensitive to some of these inhibitors. Further clinical and biological studies are needed to validate these results.

The online version of this article contains a data supplement.

Acknowledgments: We are indebted to the patients who contributed to this study.

This work was supported by grants from the Asociación Española contra el Cáncer (AECC), the Spanish Ministerio de Educación y Ciencia (SAF2008-03871), Fondos de Investigación Sanitaria (RD06/0020/0107, RD012/0036/0060 and PI10/00621), and the Sociedad para el Desarrollo Regional de Cantabria (Gobierno de Cantabria-SODERCAN). We acknowledge the biobanks of the Centro Nacional de Investigaciones Oncológicas, Instituto de Formación e Investigación Marqués de Valdecilla-Hospital Universitario Marqués de Valdecilla (RD09/0076/00076), and Fundación Jimenez Díaz (RD09/0076/00101) for their help in collecting the samples. R.M. is supported by the Fundación Conchita Rábago de Jiménez Díaz, Madrid (Spain), and M.S.-B. is supported by Miguel Servet contract CP11/00018.

Contribution: M.A.P. designed and supervised the study and reviewed the manuscript; S.M.R.-P. designed and supervised the study, evaluated the histology and immunohistochemistry, and reviewed the paper; R.M. performed the experiments, analyzed and interpreted the data, and wrote the paper; M.S.-B. performed the experiments and edited the manuscript; S.G. performed the experiments; S.M. and P.L. supplied patients’ clinical data; and F.R., M.M., J.M., J.A., and M.G.-C. provided the samples.

Conflict-of-interest disclosure: The authors declare no competing financial interests.

Correspondence: Socorro M. Rodríguez-Pinilla, Pathology Department, Fundación Jiménez Díaz, Avd Reyes Católicos, 2-28040 Madrid, Spain; e-mail: [email protected].

1
Palomero
 
T
Couronné
 
L
Khiabanian
 
H
et al. 
Recurrent mutations in epigenetic regulators, RHOA and FYN kinase in peripheral T cell lymphomas.
Nat Genet
2014
, vol. 
46
 
2
(pg. 
166
-
170
)
2
Sakata-Yanagimoto
 
M
Enami
 
T
Yoshida
 
K
et al. 
Somatic RHOA mutation in angioimmunoblastic T cell lymphoma.
Nat Genet
2014
, vol. 
46
 
2
(pg. 
171
-
175
)
3
Roncador
 
G
García Verdes-Montenegro
 
JF
Tedoldi
 
S
et al. 
Expression of two markers of germinal center T cells (SAP and PD-1) in angioimmunoblastic T-cell lymphoma.
Haematologica
2007
, vol. 
92
 
8
(pg. 
1059
-
1066
)
4
Sander
 
EE
ten Klooster
 
JP
van Delft
 
S
van der Kammen
 
RA
Collard
 
JG
Rac downregulates Rho activity: reciprocal balance between both GTPases determines cellular morphology and migratory behavior.
J Cell Biol
1999
, vol. 
147
 
5
(pg. 
1009
-
1022
)
5
Murga
 
C
Zohar
 
M
Teramoto
 
H
Gutkind
 
JS
Rac1 and RhoG promote cell survival by the activation of PI3K and Akt, independently of their ability to stimulate JNK and NF-kappaB.
Oncogene
2002
, vol. 
21
 
2
(pg. 
207
-
216
)
6
Flevaris
 
P
Li
 
Z
Zhang
 
G
Zheng
 
Y
Liu
 
J
Du
 
X
Two distinct roles of mitogen-activated protein kinases in platelets and a novel Rac1-MAPK-dependent integrin outside-in retractile signaling pathway.
Blood
2009
, vol. 
113
 
4
(pg. 
893
-
901
)
7
Yan
 
ZX
Wu
 
LL
Xue
 
K
et al. 
MicroRNA187 overexpression is related to tumor progression and determines sensitivity to bortezomib in peripheral T-cell lymphoma [published online ahead of print October 9, 2013].
Leukemia
8
Martín-Sánchez
 
E
Rodríguez-Pinilla
 
SM
Sánchez-Beato
 
M
et al. 
Simultaneous inhibition of pan-phosphatidylinositol-3-kinases and MEK as a potential therapeutic strategy in peripheral T-cell lymphomas.
Haematologica
2013
, vol. 
98
 
1
(pg. 
57
-
64
)
9
Odqvist
 
L
Sánchez-Beato
 
M
Montes-Moreno
 
S
et al. 
NIK controls classical and alternative NF-κB activation and is necessary for the survival of human T-cell lymphoma cells.
Clin Cancer Res
2013
, vol. 
19
 
9
(pg. 
2319
-
2330
)

Author notes

M.A.P. and S.M.R.-P. contributed equally to this study.

Sign in via your Institution