CD 117( C- Kit) In AML - PowerPoint Presentation

Slide1

CD 117( C- Kit) In AML

I

n The name of GodSlide2

CD 117, C- kit

CD117 is a 145

kD

protein tyrosine

kinase

also known as c-Kit.

Receptor for stem cell factor

or c-Kit

ligand

.

CD117 is expressed on

pluripotent

hematopoietic progenitor cells

(approximately

1-4%

bone marrow cells),

mast cells

, and

acute myeloid leukemic cells

(AML).

CD117 binding of c-Kit

ligand

induces

phosphorylation

of CD117 and stimulates

proliferation and survival of primitive hematopoietic stem cells

as well as

erythroid

-

committed and

granulo-monocytic

committed cells.Slide3

C

Sperling

. Expression of the stem cell factor receptor C-KIT (CD117) in acute review

Haematologica

1997; 82:617-621 Germany.

Other Names: Stem cell factor receptor, c-kit, mast cell growth factor receptor, steel factor receptor

Defects in CD117

have been linked to

severe anemia

The human gene for the c

-kit receptor is in a region in the long arm of

chromosome 4

(4q11- 4q13). Slide4

Haematologica.

1998

May;83(5

):392-7.CD117 (c-kit) is a restricted antigen of acute myeloid leukemia and characterizes early

differentiative

levels of M5 FAB subtype.

BACKGROUND AND OBJECTIVE:

The CD117 molecule is an antigen more frequently found on

early normal and leukemic hematopoietic cells

,

its

correlation with the FAB subtypes

and with

other lineage

and stage associated antigens is still

not well

established

.

CD117 antigen in 135

patients /

acute leukemia

in relationship to

de

novo or secondary origin of AML

, subtypes of FAB classification, expression of other antigens such as

CD34

,

HLA-DR

,

CD15

,

CD14, CD45RA

,

CD45RO

,

CD11b

,

CD11c

,

CD4

,

CD7

, mixed antigen co-expression (

LyAg

+ AML and

MyAg

+ ALL) and features of leukemic mass.

DESIGN AND METHODS:

1995-1997:

82 AML (including 51 cases of de novo AML, 22 cases of AML following (MDS), 9 cases of myeloid

blastic

crisis -CML and 53 ALL.

Slide5

Haematologica.

1998 May;83(5):392-7.

CD117 (c-kit) is a restricted antigen of acute myeloid leukemia and characterizes early

differentiative levels of M5 FAB subtype.

RESULTS:

CD117 antigen was found

over 10%

in

74% of AML

without significant differences of positivity between AML after MDS or BC-CML and de novo AML.

No significant correlation between FAB classification

and CD117, which was expressed in

100% of M1 and M7 cases

, in

80% of M0

cases,

in 75% of M2

cases, in

70% of M3

cases and

in 82% of M4

cases.

Instead, in M5 subtype CD117 was strictly restricted to earlier stages: ten of the eleven

M5b (91%)

cases

completely lacked CD117 antigen

expression,

whereas 100% of M5a cases were positive.

a significant direct correlation between CD117 and CD34 and CD45RA

(in all cases);

an independent expression between

CD117 and CD15

associated with a low correlation between

CD117 and HLA-DR

antigen (only in

non-

monocytic

cases

).

In

ALL

, whether of B or T lineages, surface expression of

CD117 was never observed

.

CONCLUSIONS:

We conclude that the CD117 antigen shows a high specificity for AML,

independently upon FAB classification, Slide6

Am J Clin

Pathol

.

1996 Aug;106(2):192-5. CD117/CD34 expression in leukemic blasts.

SJ, Bray RA

,

Stempora

LL

, Farhi DC.Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA.

The aim of this study was to examine the relationship between

CD117 and CD34

expression on leukemic blasts and to determine whether CD117 is related to lymphoid-associated antigen (LAA) expression in AML.

BM samples were studied from cases of AML (30 cases), (MDS) (4 cases),

myeloproliferative

disorders in blast crisis (6 cases), and ALL (5 cases).

CD117 and CD34 were analyzed by flow

cytometry

.Slide7

Am J Clin

Pathol

.

1996 Aug;106(2):192-5. CD117/CD34

expression in leukemic blasts.

SJ

,

Bray RA

,

Stempora LL, Farhi DC.Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, USA.

CD117/CD34

expression did

not correlate with FAB

subtype of AML.

CD117

is borne on

most leukemic blasts of myeloid

origin (in this study, 87% of AML, 80% of MPD-myeloid BC, and 75% of MDS)

Does

not

exclude expression of

LAA.

Although CD117 is a receptor for stem cell factor, its expression does not appear to correlate with CD34 positivity

.Slide8

. Importance of CD117 in the Evaluation of

Acute

leukemias

by Flow

Cytomtry

Department of Pathology , The University of Utah, Salt Lake City, Utah

Background.

The issue of

which specific antibodies need

to be used when

evaluating acute leukemias by flow cytometry is controversial.Methods. Recent studies have suggested that antibodies against

CD117

or c-kit are

not essential

for the assignment of blast lineage by flow

cytometry

, even though CD117 appears to be a very specific marker for myeloid lineage acute

leukemias

.

We report a case of acute myeloid leukemia

M2

subtype with an

8:21

translocation,

where the leukemic blasts expressed

CD117

,

CD19

,

and

CD15

but did

not show

definitive expression of the myeloid markers

CD13 or CD33.Slide9

Case Report

It has been proposed that

CD117 or c-kit

expression be routinely evaluated in cases of acute leukemia because of its higher myeloid lineage

specificity

as compared with CD13 or CD33 However, CD117 is not as sensitive as CD13 and CD33 for identifying acute myeloid

leukemias

(AMLs), and

recent studies

have suggested that adding anti-CD117 to a flow cytometry panel that contains anti-CD13 and anti-CD33 is not essential for the assignment of blast lineage Slide10

Case Report

51-year-old

, with a 1-month history of increasing fatigue and decreased exercise tolerance .

CBC :anemia, thrombocytopenia, marked

leukocytosis : 81,000 -including 27% blasts.BMA:

hypercellular

(95% cellularity) with an elevated myeloid to erythroid ratio (10:1) and an increased myeloid immaturity with 21% blasts.

Flow

cytometric

:representing approximately 20% of the leukocytes with low intensity CD45 staining consistent with blasts

Blasts expressed CD34, CD19, CD15, CD117, and HLA-DR without CD33 or definitive CD13 .Slide11

Case reportSlide12

Importance of CD117 in the Evaluation of Acute leukemia by flowcytometry

. Department of Pathology , The University of Utah, Salt Lake City, Utah

Staining

MPO

, TdT

,

CD22 , and CD79a :negative. Cytochemical

evaluation for

MPO

activity showed positive-staining myeloid cells and occasional blasts but

not definitive positivity on more than 3% of blasts. Nonspecific esterase staining showed only occasional positive cells. Cytogenetic :t(8;21)(q22;q22)Slide13

Case Report

DISCUSSION

Without CD117, the lack of definitive CD13 and CD33 expression with positive CD19 and CD15 staining seen in this case was more consistent with the leukemic blasts being of B cell rather than myeloid lineage.

Indeed

, CD19 CD10 B-lineage acute leukemias with CD15 expression are well described and often have abnormalities involving chromosome q23, e.g., balanced

4:11

translocations (5).

Our finding that

CD117 is sometimes essential in evaluating cases of acute leukemias by flow cytometry contrasts with the recent study by Hans et at. (3). It is well known that the

contribution of flow

cytometry

to a diagnosis of acute leukemia is

variable

and can depend on what

other information

or data may be available. Given the

marrow

findings of

left-shifted myeloid

hyperSlide14

Case Report

AML

s that

lack CD13 and CD33

expression are rare but may account for approximately 4% of cases

It is interesting that absent surface expression of CD13 and CD33

appears to be associated more frequently with

the M2

subtype of AML;

all four cases evaluated by Arber et al. (7) were M2-subtypes with 8:21 translocations, and three of eight cases studied by Kragulic et al. (6) were M2 subtypes. None of the CD13 and CD33 AMLs in these studies was reported to be positive for

CD19

, as in our case.

However, approximately

80% of AMLs with 8:21

translocations are thought to

express CD19

(7,8), so it is likely that additional cases of CD19 AML M2 that also lack CD13 and CD33 will be encountered by othersSlide15

Importance of CD117 in the Evaluation of acute leukemia by flowcytometry

Department of Pathology , The University of Utah, Salt Lake City, Utah

Moreover, because

the sensitivity of CD117

in AML appears to be

highes

t for the M2 subtype, which is found in approximately 80% of cases (1,3), CD117 likely will be essential when evaluating other

CD19, CD13, and CD33

AML cases by flow

cytometry

to correctly identify the blast lineage.In conclusion: this study demonstrated that anti- CD117 antibodies are sometimes essential when evaluating AMLs by flow cytometry. In addition, this case presented an unusual AML phenotype that likely will be

encountered by others and

could be mistakenly thought to represent acute

biphenotypic

leukemia

because of the

CD19

expression and paucity of

myeloid

markers.

Because CD117 is sometimes essential, it

should be available

for use in

any flow

cytometry

laboratory

that evaluates acute

leukemias

. However, because of

cost and possible technical issues related to handling additional tubes,

we recommend that CD117 be

reserved

for

difficult

or

ambiguous cases

and

left out

of

screening

or

initial core panels

.Slide16

Christine P .Usefulness of Anti-CD117

in the

Flow

Cytometric

Analysis

of

Acute Leukemia. Am J Clin

Pathol

2002;117:301-305

We assessed the diagnostic usefulness of adding anti-CD117 to our existing flow cytometric profile in the analysis of 150 consecutive cases of: acute leukemia (

de novo or relapsed

acute myelogenous

leukemia

[AML], AML arising in

myelodysplastic

syndrome

,

blast crisis of

chronic

myelogenous

leukemia

[CML], acute lymphoblastic leukemia

,

acute unclassifiable leukemia

, and

biphenotypic

leukemia).

CD117 was expressed on

more than 10% of blasts

in

64

%

of de novo

AMLs

(42/66),

95%

of

relapsed AMLs

(19/20

), 75%

of AMLs arising from a

myelodysplastic

syndrome

(6/8), and

25%

of

myeloid blast

crisis in

CMLs

(1/4).

Slide17

Christine P .Usefulness of Anti-CD117 in the Flow

Cytometric

Analysis

of Acute Leukemia

. Am J Clin

Pathol 2002;117:301-305

CD117 was

not expressed

in

acute lymphoblastic, acute biphenotypic, or unclassified leukemia or lymphoid blast crisis of CML. The specificity, positive predictive value, sensitivity,

and negative predictive value of CD117 for AML were

100%,

100%,

69%,

and 62%, respectively.

CD117

is a

specific marker

for

myeloblastic

leukemias

.

Sensitivity

is greatest in French-American-British

M2

and

relapsed AML

.

Intensity of CD117 expression is dim.

Despite the high specificity and positive predictive value, the addition of anti-CD117 to our panel did not prove essential for the

assignment of blast lineage.Slide18

CD117 Expression in Acute

Myelogenous

Leukemia

Subtypes*

FAB Class No. of Cases No. (%) of CD117+ Cases

number of patients Number of CD 117 positive & Percentage

M0 5 4 (80)

M1 10 6 (60)

M2 21 19 (90)M3 4 2 (50)M4 7 5 (71)M5a 2 0M5b 5 1 (20)M7 2 1 (50)

* According to the French-American-British (FAB) classificationSlide19

Usefulness of

CD117

,

CD13

, and CD33 for Discriminating

Acute Myeloid

From Acute Lymphoid Leukemia

CD117 CD13 CD33 CD13 and/ or CD33

SPS: %100 86 74 64

SEN: %69 84 86 99

Positive predictive value (%) 100 /92/ 87/ 86Negative predictive value (%) 62/ 72/ 72 /97Slide20

Christine P .Usefulness of Anti-CD117

in the

Flow

Cytometric

Analysis

of

Acute Leukemia. Am J Clin

Pathol

2002;117:301-305

CD117 is a specific marker for AML arising de novo orin association with

myelodysplasti

c syndromes.

Overall, we found CD117 expression in

69%

of

myeloid leukemic

processes (

AML

,

MDS-AML

, and

CML myeloid blast crisis

).

Other

s have reported CD117 expression by flow

cytometric

analysis in

23% to 91%

of

AML

cases.

Our findings

are in agreement with the largest studies that found CD117 in

63% to 67%

of AML cases.

We found

no CD117

expression in

ALL

.

Other studies

have found

rare

examples of expression in

ALL

, more frequently those of

T-lineage

than of B-lineage .

Our study included 7 cases of T-ALL.Slide21

Christine P .Usefulness of Anti-CD117 in the Flow

Cytometric

Analysis

of Acute Leukemia

. Am J Clin

Pathol 2002;117:301-305

Findings in a German cooperative study and the Children’s Cancer Group, CD117 status seems to

lack

prognostic significance in AML.CD117 expression does not seem to be a reliable predictor of

FAB AML subtype

Although CD117 has a high specificity, it is not as sensitive as CD13 or CD33 for detecting myeloid leukemic.

Approximately

30%

of acute myeloid leukemia

did not stain

with

anti-CD117

.Slide22

CD34/CD117 co-expression in

Leukemia

Research

Volume 24, Issue 3

, Pages 201-206, March 2000childhood acute leukemia

.

CD117

protein is expressed by the

haemopoietic

stem cells

demonstrated on the primitive CD34 positive and also blasts of 30–100% of AML cases, but rarely on lymphoblasts.

Therefore

several investigators

have

used CD117 expression

to

exclude

lymphoblastic origin

of blasts.

However,

conflicting results

exist in the

literature

.

We investigated

CD34 and CD117

status at initial presentation

of

232 children with acute leukemia

CD34

was commonly expressed in

all types of acute

leukemias

, whereas CD117 molecule seemed to be a more specific marker for leukemia of myeloid origin being demonstrated

on >5% of blasts in 60 out of 73 cases of AML patients, but rarely detected in ALL (9/140 patients). Slide23

C Sperling . Expression of the stem cell factor receptor C-KIT (CD117) in

acute review

Together with its

ligand

, the stem cell factor (SCF), it plays an

important

role in

hematopoiesis

.

Membrane expression of

CD117 can be found on leukemic blasts from approximately 60% of adult

and

childhood AML

patients, often associated with an

immature

immunophenotype

(

CD34).

Moreover, AML with t(8;21) are frequently CD117 positive.

Despite earlier reports,

most recent studies

have

not

been able to demonstrate any significant

prognostic

impact of CD117 expression in either childhood or adult AML.

A small proportion of T-lineage ALL (9%),

mainly consisting of immature pro-T/pre-T-ALL, is CD117 positive.

CD117 expression is rare in

B-cell-precursor-ALL

and occurs in less than

3% of cases

.

. Slide24

C Sperling . Expression of the stem cell factor receptor C-KIT (CD117) in acute review

In addition to its expression in normal

hematopoiesis

, c

-kit has been found on :

AML blasts

,as well as myeloid

,

erythroid

,

megakaryocytic and lymphoid cell lines. Non-hematopoietic cells expressing c-kit include normal tissues such as epithelial cells of the breast

,

parotid

and

dermal sweat glands

,

melanocytes

,

central nervous system

(particularly in the

cerebellum

, the

hippocampus

, and the

dorsal horn of the spinal cord

),

placenta

,

interstitial cells of the testes

and

ovaries

as well as tissues from

small cell lung cancer

,

breast

canceror

melanoma

, and

cell lines derived from the respective tumors

.Slide25

C Sperling . Expression of the stem cell factor receptor C-KIT (CD117) in acute review

Most recent studies, including both

childhood

and

adult AML, were

unable

to demonstrate anysignificant differences in CR rate, survival rate, and

event-free survival

between

CD117-positive

and CD117-negative cases. Therefore, these studies do not confirm previous results suggesting that CD117 contributes to the identification of clinically-relevant AML subgroups.