Seven Variants Including Four New Philadelphia Translocations Reinhard Becher, Jing-Ying Qiu, Annette Parr, Edith Wendehorst, and Carl-G. Schmidt
ABSTRACT: This paper reports on seven atypical Philadelphia chromosome translocations in chronic myelocytic leukemia. Three of them. a t(16;22), t(17;22), and t(9;14;22) have already been observed before, while the t(X;9;11 ;22), t(X;22), t(3;22), and t(3;4;9;22) are newly reported.
INTRODUCTION
In chronic myelocytic leukemia (CML), translocations other than t(9;22) occur in less than 10% [1, 2] of cases. Cytogenetically simple atypical Philadelphia (Ph) chromosome translocations involving a chromosome other than # 9 can be distinguished from complex translocations of three or more chromosomes. Chromosome 9 is always involved in those translocations, even if undetectable by b a n d i n g studies. Its presence is revealed by the translocation of sequences of the c-abl protooncogene to the Ph chromosome [3-7]. The present article describes seven CML patients with variant Ph translocations: four with a simple atypical translocation (cases 1, 2, 4, and 7), and three with complex translocations. Four of these are newly reported (cases 4 7), and two of them also involve the X chromosome.
PATIENTS A N D METHODS
All seven patients first presented with a clinically typical Ph-positive CML in the chronic phase of disease. At time of this report, case 7 had already progressed into blast crisis. Age, sex of patients, and the n u m b e r of analyzed metapbases are given in Table 1. G-banded chromosome studies were performed between 1987 and 1988 with bone marrow cells at time of diagnosis using conventional Giemsa staining after short-term trypsin treatment.
RESULTS
The seven abnormal Ph translocations consisted of four cases with simple translocations between chromosomes 22, and 3, 16, 17, or X. Cytogenetically, chromosomes 9 appeared normal. The respective karyotypes (cases 1, 2, 4, and 7) are
From the Innere Universit~tsund Poliklinik,WestdeutschesTumorzentrum,Essen, F.R.G. Address reprint requests to: Prof. Dr. Reinhard Becher, Westdeutsches Tumorzentrum. Innere Universit8ts und Poliklinik (Tumorforschung), Hufelandstr. 55, D-4300 Essen 1. F.R.G. Received February 1, 1989; accepted May 15. 1989.
181 © 1990 ElsevierSciencePublishingCo., Inc. 655 Avenueof the Americas,New York, NY 10010
Cancer Genet Cytogenet44:181 186 (1990) 0165-4608/90/S03.50
182
R. Becher et al.
Table 1
Clinical and cytogenetic data of the seven patients
Patient
Age/sex
Cells analyzed
1 2 3 4 5 6 7
26/F 24/M 57/M 45/M 54/M 40/M 25/M 29/M"
20 20 20 2O 20 20 12 2O
Karyotype 46,XX,t(16;22)(pl 3 ;qll) 46,XY,t(17;22)(pl 3;q12) 46,XY,t(9;14;22)(q34;q11;q11) 46,XY,t(3;22)(q28;ql 1) 46,Y,t(X;9;11:22)(p11;q34;q12;q11) 46,XY.t(3;4;9;22)(q27;q31;q22;q11) 46,Y,t{X;22)(q28;q11) 47,Y,t(X;22),+8,+21, 18,+dmin
No. cases reported [8] 6 12 1 0 0 0 0
After onset of blast crisis.
46,XX,t(16;22)(p13;q11), 46,XY,t(17;22)(p13;q11}, 46,XY,t(3;22)(q28;q11), and 46, Y,t(X;22)(q28;q11). In cases 3, 5, and 6, complex translocations were found. Case 3 showed the formation of a 9q+ marker. Our interpretation of this marker is that part of the long arm of 22 is interposed between the terminal end of 9q and the translocated long arm of c h r o m o s o m e 14, as revealed by a broad light band. In case 5, the c o m p l e x Ph translocation can be designated as a t(X;9;11;22)(p11;q34;q12;q11). The formation of this c o m p le x translocation is interpreted below. Partial karyotypes of cases 1 - 3 are s h o w n in Figure 1. Chromosome studies in case 6 revealed the karyotype 46,XY,t[3;4;9;22)(q27;q31;q34;q11). As shown in the detailed karyotypic description, we suspect two breakpoints on the long arm of chromosome 9. It seems remarkable that c h r o m o s o m e 4 received material of chromosomes 9 and 3 at the same time. A detailed description of markers in addition to the Ph c h r o m o s o m e is: Case 1: 16qter--->16p13::22q11-->22qter Case 2:
17qter--,17p13::22qll--,22qter;22pter
Case 3: 9pter--~9q34::22q11-->22q12::14qll--~14qter;14pter-->14q11::22q12-->22qter Case 4: 3pter-->3q28::22q11--~22qter Case 5: t(X;9;11;22)(Xqter-+Xp11::11q12--,llqter;9pter--~9q34::Xp11--+ Xpter;11pter--~11q12 ::22q11--~22qter
P
case1 ~ 99 case2 ~ i~ 99 w~ case3 ~ b~,,
1616p+ 22Ph P
17 17p+ 22Ph
1",, 9 9q,
1,414q- 2"2Ph
Figure 1 Partial karyotypes of cases 1-3 presenting with a t(16;22), a t(17;22}, and a t(9;14;22), respectively.
18 3
Four New Ph Translocations
,.j
t
1
2
3
6
7
8
13
14
15
t p
~
19
20
......
~i
Figure 2
4
5
10
11
12
16
17
18
21
22
X Y
~i
9
Representative karyotype of case 4 with a t(3;22).
Case 6: 3pter-~3q27::22q11--~22qter;4pter--~4q31::9q34--~9q22::3q27--~3qter;9pter-~ 9q22::4q31::4qter;22pter Case 7: Xpter--~Xq28::22q11--~22qter. Representative karyotypes of cases 4 - 7 are shown in Figures 2-5, respectively.
DISCUSSION Up to now, more then 300 cases of Ph-positive CML with variant translocations have been described, about half of them as complex translocations and the majority involving three chromosomes, but also i n c l u d i n g four- and five-way translocations. The atypical translocations observed in cases 1, 2, and 3 have already been reported before with different frequencies, as shown in Table 1 [8]. Translocations t(3;22) have already been reported before, but involving other breakpoints [15, 16]. One reason to report abnormal Ph translocations is the possible establishment of a n o n r a n d o m i n v o l v e m e n t of specific chromosomes or breakpoints. It seems remarkable that sex chromosomes are very rarely affected. Although to our knowledge there are no reports in which the Y chromosome was structurally altered, there are only five cases, i n c l u d i n g the present two, that show an initial involvement of the X chromosome in an aberrant Ph translocation, as shown in Table 2. Both cases (cases 5 and 7) represent new translocations also involving new breakpoints on the X chromosome. A n u n u s u a l feature of case 7, which was also studied in blast crisis, was the appearance of four double m i n u t e s (dmin), which is a rare event associated with poor prognosis that has been reported in only three cases with a standard translocation [8]. Other cases in the literature with X chromosome involvement present standard translocations [8] or an atypical h i d d e n Ph translocation [13] with additional clonal evo-
P~
0
L
•
$
+
.~, ~~0~
D~ ~
:
-,,,,l
e4
1 4
L
I~3
o
o r~
M c~
=
..
©
cD
=
~ ,~,
i
.4-"
~
/
4
04
~4 Zm~ 4
+
~ 4
~ + 8
~
Go
185
Four New Ph Translocations
~ ~i~
2
O
3
....
-
7
8
13
14
15
19
20
Figure 5
4
9
..... ~ DM
5
~i¸ ~
a ~
w~
10
11
12
16
17
18
21
22
X
Y
Representative karyotype of case 7 with a t(X;22).
lution involving the X chromosome. This constellation is also rare, as only seven cases of this category have been reported so far [8]. One paper also described a Phnegative CML with a translocation involving the X chromosome [141. It was confirmed that the whole group of CML patients with abnormal Ph translocations have the same clinical, hematologic, and prognostic features as known from standard translocations [41. Therefore, it is presently accepted that variant Ph translocations have little or no influence on the course of disease. The atypical breakpoints involved, however, are n o n r a n d o m l y distributed, and a review of the reported cases shows that several specific types of abnormal translocations have already been reported in a considerable n u m b e r of cases, as in our cases 2 and 4. Thus. it should be of interest to search for differences in the expression and prognosis of CML in specific subgroups caused by identical atypical translocations. The whole group of patients with atypical translocations could constitute a mixture of cases with better or worse prognosis according to specific breakpoints. This approach seems promising,
Table 2
Atypical translocations involving the X chromosome in Ph-positive CML
Date
Karyotype
References
1979 1979 1981 1988 1988
t(X;9;22)(q27;q34;q12) t(X;22)(p22:q11) t(X;9;22)(q11;q22;q12) t(X;9;11;22)(p11;q34;q12;q11) t(X;22)(q28;q11)
Dallapiccola and Alimena {9] Hossfeld and K6hler [10] Fitzgerald et al. [11] Present report Present report
186
R. B e c h e r et al.
as De B r a e k e l e e r [12] s u g g e s t e d a close r e l a t i o n s h i p b e t w e e n c h r o m o s o m e breakp o i n t s of t h e m o s t f r e q u e n t a t y p i c a l P h t r a n s l o c a t i o n s a n d t h e l o c a t i o n of p r o t o o n c o genes. B e c a u s e of t h e r a r i t y of cases, s u c h a n i n v e s t i g a t i o n c o u l d o n l y be m a d e b y a n i n t e r n a t i o n a l l y s u p p o r t e d r e t r o s p e c t i v e a n a l y s i s b a s e d o n t h e r e e v a l u a t i o n a n d foll o w - u p of p u b l i s h e d cases. This work was supported by the Sonderforschungsbereich SFB 102 of the Deutsch Forschungsgemeinschaft and a grant of the Scientific Exchange Program of the Universities Essen and Beijing given to J.-Y. Q.
REFERENCES 1. First International Workshop on Chromosomes in Leukemia (1978): Chromosomes in Ph positive chronic granulocytic leukemia. Br J Haematol 39:305-309. 2. Sandberg AA (1980): Chromosomes and causation of h u m a n cancer and leukemia: XI. The Ph and other translocations in CML. Cancer 46:2221-2226. 3. Bartram CR, Anger B, Carbonell F, Kleihauer E (1985): involvement of chromosome 9 in variant Ph translocation. Leukemia Res 9:1133-1137. 4. Sandberg AA, Gemmill RM, Hecht BK, Hecht F (1986): The Philadelphia chromosome: A model of cancer molecular cytogenetics. Cancer Genet Cytogenet 21:129-146. 5. Hagemeijer A, et al. (1984): Is the chromosomal region 9q34 always involved in variants of the Ph translocation? Cancer Genet Cytogenet 13:1-16. 6. Hagemeijer A, et al. (1985): Translocation of c-abl to "masked" Ph in chronic myeloid leukemia. Cancer Genet Cytogenet 18:95-104. 7. Morris CM, et al. (19881: A cytogenetic and molecular analysis of five variant Philadelphia translocations in chronic myeloid leukemia. Cancer Genet Cytogenet ',35:179-197. 8. Mitehnan F (1988): Catalog of (~'hromosome Aberrations in Cancer, 3rd ed. Alan R. Liss, New York. 9. Dallapiccola B, Alimena G (1979): Inactive normal X in a female leukemic patient with an acquired X/autosome translocation. Human Genet 48:69-177. 10. Hossfeld DK, KOhler S (1979): New translocations in chronic granulocytic leukemia: t(X;22) (q26;q11) and t(15:22)(q26;q11). Br l Haematol 41:185-191. 11. Fitzgerald PH, et al. (1981): A complex Ph translocation in a patient with primary thrombocythaemia. Br J Haematol 4 7 : 5 7 1 - 5 7 5 . 12. De Braekeleer M (1986): Breakpoints in variant Philadelphia translocations in chronic myeloid leukemia. Blut 53:301-304. 13. Engel E, McGee B, Flexner J, Krantz SB (1975): Translocation of Philadelphia chromosome onto the 17 short arm ill chronic myeloid leukemia: A second example. N Engl J Med 293:666. 14. O'Malley FM, Garson OM (1985): Chronic granulocytic leukemia: Correlation of blastic translocation type with karyotypic evolution. Am I Haematol 20:313-332. 15. Pravtcheva D, et al. (1976): A new translocation in chronic myelogenous leukemia. Hum Genet 32:229-232. 16. Potter AM, et al. (1981): Significance of non-standard Philadelphia chromosomes in chronic granulocytic leukaemia. Br J Cancer 44:51-54.
ABSTRACT: This paper reports on seven atypical Philadelphia chromosome translocations in chronic myelocytic leukemia. Three of them. a t(16;22), t(17;22), and t(9;14;22) have already been observed before, while the t(X;9;11 ;22), t(X;22), t(3;22), and t(3;4;9;22) are newly reported.
INTRODUCTION
In chronic myelocytic leukemia (CML), translocations other than t(9;22) occur in less than 10% [1, 2] of cases. Cytogenetically simple atypical Philadelphia (Ph) chromosome translocations involving a chromosome other than # 9 can be distinguished from complex translocations of three or more chromosomes. Chromosome 9 is always involved in those translocations, even if undetectable by b a n d i n g studies. Its presence is revealed by the translocation of sequences of the c-abl protooncogene to the Ph chromosome [3-7]. The present article describes seven CML patients with variant Ph translocations: four with a simple atypical translocation (cases 1, 2, 4, and 7), and three with complex translocations. Four of these are newly reported (cases 4 7), and two of them also involve the X chromosome.
PATIENTS A N D METHODS
All seven patients first presented with a clinically typical Ph-positive CML in the chronic phase of disease. At time of this report, case 7 had already progressed into blast crisis. Age, sex of patients, and the n u m b e r of analyzed metapbases are given in Table 1. G-banded chromosome studies were performed between 1987 and 1988 with bone marrow cells at time of diagnosis using conventional Giemsa staining after short-term trypsin treatment.
RESULTS
The seven abnormal Ph translocations consisted of four cases with simple translocations between chromosomes 22, and 3, 16, 17, or X. Cytogenetically, chromosomes 9 appeared normal. The respective karyotypes (cases 1, 2, 4, and 7) are
From the Innere Universit~tsund Poliklinik,WestdeutschesTumorzentrum,Essen, F.R.G. Address reprint requests to: Prof. Dr. Reinhard Becher, Westdeutsches Tumorzentrum. Innere Universit8ts und Poliklinik (Tumorforschung), Hufelandstr. 55, D-4300 Essen 1. F.R.G. Received February 1, 1989; accepted May 15. 1989.
181 © 1990 ElsevierSciencePublishingCo., Inc. 655 Avenueof the Americas,New York, NY 10010
Cancer Genet Cytogenet44:181 186 (1990) 0165-4608/90/S03.50
182
R. Becher et al.
Table 1
Clinical and cytogenetic data of the seven patients
Patient
Age/sex
Cells analyzed
1 2 3 4 5 6 7
26/F 24/M 57/M 45/M 54/M 40/M 25/M 29/M"
20 20 20 2O 20 20 12 2O
Karyotype 46,XX,t(16;22)(pl 3 ;qll) 46,XY,t(17;22)(pl 3;q12) 46,XY,t(9;14;22)(q34;q11;q11) 46,XY,t(3;22)(q28;ql 1) 46,Y,t(X;9;11:22)(p11;q34;q12;q11) 46,XY.t(3;4;9;22)(q27;q31;q22;q11) 46,Y,t{X;22)(q28;q11) 47,Y,t(X;22),+8,+21, 18,+dmin
No. cases reported [8] 6 12 1 0 0 0 0
After onset of blast crisis.
46,XX,t(16;22)(p13;q11), 46,XY,t(17;22)(p13;q11}, 46,XY,t(3;22)(q28;q11), and 46, Y,t(X;22)(q28;q11). In cases 3, 5, and 6, complex translocations were found. Case 3 showed the formation of a 9q+ marker. Our interpretation of this marker is that part of the long arm of 22 is interposed between the terminal end of 9q and the translocated long arm of c h r o m o s o m e 14, as revealed by a broad light band. In case 5, the c o m p l e x Ph translocation can be designated as a t(X;9;11;22)(p11;q34;q12;q11). The formation of this c o m p le x translocation is interpreted below. Partial karyotypes of cases 1 - 3 are s h o w n in Figure 1. Chromosome studies in case 6 revealed the karyotype 46,XY,t[3;4;9;22)(q27;q31;q34;q11). As shown in the detailed karyotypic description, we suspect two breakpoints on the long arm of chromosome 9. It seems remarkable that c h r o m o s o m e 4 received material of chromosomes 9 and 3 at the same time. A detailed description of markers in addition to the Ph c h r o m o s o m e is: Case 1: 16qter--->16p13::22q11-->22qter Case 2:
17qter--,17p13::22qll--,22qter;22pter
Case 3: 9pter--~9q34::22q11-->22q12::14qll--~14qter;14pter-->14q11::22q12-->22qter Case 4: 3pter-->3q28::22q11--~22qter Case 5: t(X;9;11;22)(Xqter-+Xp11::11q12--,llqter;9pter--~9q34::Xp11--+ Xpter;11pter--~11q12 ::22q11--~22qter
P
case1 ~ 99 case2 ~ i~ 99 w~ case3 ~ b~,,
1616p+ 22Ph P
17 17p+ 22Ph
1",, 9 9q,
1,414q- 2"2Ph
Figure 1 Partial karyotypes of cases 1-3 presenting with a t(16;22), a t(17;22}, and a t(9;14;22), respectively.
18 3
Four New Ph Translocations
,.j
t
1
2
3
6
7
8
13
14
15
t p
~
19
20
......
~i
Figure 2
4
5
10
11
12
16
17
18
21
22
X Y
~i
9
Representative karyotype of case 4 with a t(3;22).
Case 6: 3pter-~3q27::22q11--~22qter;4pter--~4q31::9q34--~9q22::3q27--~3qter;9pter-~ 9q22::4q31::4qter;22pter Case 7: Xpter--~Xq28::22q11--~22qter. Representative karyotypes of cases 4 - 7 are shown in Figures 2-5, respectively.
DISCUSSION Up to now, more then 300 cases of Ph-positive CML with variant translocations have been described, about half of them as complex translocations and the majority involving three chromosomes, but also i n c l u d i n g four- and five-way translocations. The atypical translocations observed in cases 1, 2, and 3 have already been reported before with different frequencies, as shown in Table 1 [8]. Translocations t(3;22) have already been reported before, but involving other breakpoints [15, 16]. One reason to report abnormal Ph translocations is the possible establishment of a n o n r a n d o m i n v o l v e m e n t of specific chromosomes or breakpoints. It seems remarkable that sex chromosomes are very rarely affected. Although to our knowledge there are no reports in which the Y chromosome was structurally altered, there are only five cases, i n c l u d i n g the present two, that show an initial involvement of the X chromosome in an aberrant Ph translocation, as shown in Table 2. Both cases (cases 5 and 7) represent new translocations also involving new breakpoints on the X chromosome. A n u n u s u a l feature of case 7, which was also studied in blast crisis, was the appearance of four double m i n u t e s (dmin), which is a rare event associated with poor prognosis that has been reported in only three cases with a standard translocation [8]. Other cases in the literature with X chromosome involvement present standard translocations [8] or an atypical h i d d e n Ph translocation [13] with additional clonal evo-
P~
0
L
•
$
+
.~, ~~0~
D~ ~
:
-,,,,l
e4
1 4
L
I~3
o
o r~
M c~
=
..
©
cD
=
~ ,~,
i
.4-"
~
/
4
04
~4 Zm~ 4
+
~ 4
~ + 8
~
Go
185
Four New Ph Translocations
~ ~i~
2
O
3
....
-
7
8
13
14
15
19
20
Figure 5
4
9
..... ~ DM
5
~i¸ ~
a ~
w~
10
11
12
16
17
18
21
22
X
Y
Representative karyotype of case 7 with a t(X;22).
lution involving the X chromosome. This constellation is also rare, as only seven cases of this category have been reported so far [8]. One paper also described a Phnegative CML with a translocation involving the X chromosome [141. It was confirmed that the whole group of CML patients with abnormal Ph translocations have the same clinical, hematologic, and prognostic features as known from standard translocations [41. Therefore, it is presently accepted that variant Ph translocations have little or no influence on the course of disease. The atypical breakpoints involved, however, are n o n r a n d o m l y distributed, and a review of the reported cases shows that several specific types of abnormal translocations have already been reported in a considerable n u m b e r of cases, as in our cases 2 and 4. Thus. it should be of interest to search for differences in the expression and prognosis of CML in specific subgroups caused by identical atypical translocations. The whole group of patients with atypical translocations could constitute a mixture of cases with better or worse prognosis according to specific breakpoints. This approach seems promising,
Table 2
Atypical translocations involving the X chromosome in Ph-positive CML
Date
Karyotype
References
1979 1979 1981 1988 1988
t(X;9;22)(q27;q34;q12) t(X;22)(p22:q11) t(X;9;22)(q11;q22;q12) t(X;9;11;22)(p11;q34;q12;q11) t(X;22)(q28;q11)
Dallapiccola and Alimena {9] Hossfeld and K6hler [10] Fitzgerald et al. [11] Present report Present report
186
R. B e c h e r et al.
as De B r a e k e l e e r [12] s u g g e s t e d a close r e l a t i o n s h i p b e t w e e n c h r o m o s o m e breakp o i n t s of t h e m o s t f r e q u e n t a t y p i c a l P h t r a n s l o c a t i o n s a n d t h e l o c a t i o n of p r o t o o n c o genes. B e c a u s e of t h e r a r i t y of cases, s u c h a n i n v e s t i g a t i o n c o u l d o n l y be m a d e b y a n i n t e r n a t i o n a l l y s u p p o r t e d r e t r o s p e c t i v e a n a l y s i s b a s e d o n t h e r e e v a l u a t i o n a n d foll o w - u p of p u b l i s h e d cases. This work was supported by the Sonderforschungsbereich SFB 102 of the Deutsch Forschungsgemeinschaft and a grant of the Scientific Exchange Program of the Universities Essen and Beijing given to J.-Y. Q.
REFERENCES 1. First International Workshop on Chromosomes in Leukemia (1978): Chromosomes in Ph positive chronic granulocytic leukemia. Br J Haematol 39:305-309. 2. Sandberg AA (1980): Chromosomes and causation of h u m a n cancer and leukemia: XI. The Ph and other translocations in CML. Cancer 46:2221-2226. 3. Bartram CR, Anger B, Carbonell F, Kleihauer E (1985): involvement of chromosome 9 in variant Ph translocation. Leukemia Res 9:1133-1137. 4. Sandberg AA, Gemmill RM, Hecht BK, Hecht F (1986): The Philadelphia chromosome: A model of cancer molecular cytogenetics. Cancer Genet Cytogenet 21:129-146. 5. Hagemeijer A, et al. (1984): Is the chromosomal region 9q34 always involved in variants of the Ph translocation? Cancer Genet Cytogenet 13:1-16. 6. Hagemeijer A, et al. (1985): Translocation of c-abl to "masked" Ph in chronic myeloid leukemia. Cancer Genet Cytogenet 18:95-104. 7. Morris CM, et al. (19881: A cytogenetic and molecular analysis of five variant Philadelphia translocations in chronic myeloid leukemia. Cancer Genet Cytogenet ',35:179-197. 8. Mitehnan F (1988): Catalog of (~'hromosome Aberrations in Cancer, 3rd ed. Alan R. Liss, New York. 9. Dallapiccola B, Alimena G (1979): Inactive normal X in a female leukemic patient with an acquired X/autosome translocation. Human Genet 48:69-177. 10. Hossfeld DK, KOhler S (1979): New translocations in chronic granulocytic leukemia: t(X;22) (q26;q11) and t(15:22)(q26;q11). Br l Haematol 41:185-191. 11. Fitzgerald PH, et al. (1981): A complex Ph translocation in a patient with primary thrombocythaemia. Br J Haematol 4 7 : 5 7 1 - 5 7 5 . 12. De Braekeleer M (1986): Breakpoints in variant Philadelphia translocations in chronic myeloid leukemia. Blut 53:301-304. 13. Engel E, McGee B, Flexner J, Krantz SB (1975): Translocation of Philadelphia chromosome onto the 17 short arm ill chronic myeloid leukemia: A second example. N Engl J Med 293:666. 14. O'Malley FM, Garson OM (1985): Chronic granulocytic leukemia: Correlation of blastic translocation type with karyotypic evolution. Am I Haematol 20:313-332. 15. Pravtcheva D, et al. (1976): A new translocation in chronic myelogenous leukemia. Hum Genet 32:229-232. 16. Potter AM, et al. (1981): Significance of non-standard Philadelphia chromosomes in chronic granulocytic leukaemia. Br J Cancer 44:51-54.
