Supplemental table 1. upregulated in tumors containing phosphorylated STAT3 and phosphorylated STAT5 compared to tumors with only phosphorylated STAT3.

name Gene ID fold t statistic P value

change

Amphiregulin (schwannoma-derived growth factor) 374 5.49 4.272 0.000631

Spectrin repeat containing, nuclear envelope 2 23224 4.35 2.148 0.045754

SMAD specific E3 ubiquitin ligase 1 57154 4.35 2.168 0.041519

Ras suppressor protein 1 6251 4.01 2.291 0.032122 amphiregulin (schwannoma-derived growth factor) 374 3.79 3.601 0.002142 chemokine (C-X-C motif) ligand 2 2920 3.17 2.201 0.044089 laminin, gamma 2 3918 3.11 2.623 0.020121 interferon, alpha-inducible protein (clone IFI-6-16) 2537 2.96 2.153 0.048022 transmembrane 4 L six family member 1 4071 2.9 2.396 0.025563

2'-5'-oligoadenylate synthetase 2, 69/71kDa 4939 2.78 2.143 0.047492 guanylate cyclase 1, soluble, beta 2 2974 2.72 2.469 0.021815 phorbol-12-myristate-13-acetate-induced protein 1 5366 2.64 2.494 0.022427

Mesenchymal stem cell protein DSC43 51333 2.64 2.311 0.031991

PARK2 co-regulated 135138 2.62 2.464 0.023734 myxovirus (influenza virus) resistance 1, interferon- 4599 2.61 2.172 0.046523 inducible protein p78 (mouse) /// myxovirus (influenza virus) resistance 1, interferon-inducible protein p78

(mouse) solute carrier family 16 (monocarboxylic acid 6566 2.48 2.341 0.030719 transporters), member 1

UDP-N-acetyl-alpha-D-galactosamine:polypeptide N- 2591 2.47 2.216 0.039053 acetylgalactosaminyltransferase 3 (GalNAc-T3) deoxynucleotidyltransferase, terminal 1791 2.42 2.252 0.035746 toll-like receptor 3 7098 2.36 3.503 0.002153 glycosyltransferase 28 domain containing 1 55849 2.32 3.846 0.001546

G protein-coupled receptor, family C, group 5, member A 9052 2.27 2.129 0.048845 early growth response 3 1960 2.27 2.819 0.010601 phospholipase A2, group X 8399 2.21 2.104 0.04992 coagulation factor II (thrombin) receptor-like 1 2150 2.21 2.5 0.023593 receptor superfamily, member 11b 4982 2.18 2.31 0.030837

(osteoprotegerin) ets variant gene 7 (TEL2 oncogene) 51513 2.18 2.849 0.009355 pannexin 1 24145 2.17 4.544 0.000188 zinc finger protein 154 (pHZ-92) 7710 2.13 2.637 0.015235

G1 to S phase transition 2 /// G1 to S phase transition 2 23708 2.13 2.408 0.025982 tripartite motif-containing 58 25893 2.12 2.449 0.022811

S100 calcium binding protein A2 6273 2.1 2.64 0.016791 hypothetical protein LOC284837 284837 2.08 2.407 0.025377 antigen p97 (melanoma associated) identified by 4241 2.08 2.196 0.040537 monoclonal antibodies 133.2 and 96.5 stomatin 2040 2.07 2.655 0.01482

Tumor necrosis factor (ligand) superfamily, member 10 /// 8743 2.06 2.342 0.029792

Tumor necrosis factor (ligand) superfamily, member 10 fibronectin leucine rich transmembrane protein 3 23767 2.02 2.297 0.032343 sterile alpha motif and leucine zipper containing kinase 51776 1.99 3.12 0.004986

AZK dual specificity phosphatase 10 11221 1.97 2.831 0.009954 sterile alpha motif domain containing 9 54809 1.96 3.614 0.001929 arylsulfatase D 414 1.94 2.598 0.016876 Adaptor-related protein complex 1, sigma 2 subunit 8905 1.94 2.519 0.023887

KIAA0701 protein 23074 1.93 2.391 0.026618 annexin A3 306 1.92 2.32 0.030282 7 open reading frame 6 219285 1.91 2.95 0.008886

UDP-Gal:betaGlcNAc beta 1,4- galactosyltransferase, 2683 1.9 2.395 0.027939 polypeptide 1 hypothetical gene supported by BC007071 91687 1.9 2.273 0.033786 elongation factor, RNA polymerase II, 2 22936 1.9 2.85 0.011154 membrane targeting (tandem) C2 domain containing 1 123036 1.89 2.464 0.022009 follistatin 10468 1.89 2.409 0.026879

SLIT and NTRK-like family, member 2 84631 1.88 2.542 0.018604 gastrin-releasing peptide 2922 1.88 2.587 0.017343 zinc finger and BTB domain containing 1 22890 1.87 2.54 0.018734 catenin (cadherin-associated protein), alpha 3 29119 1.87 2.587 0.017231 v-jun sarcoma virus 17 oncogene homolog (avian) 3725 1.85 3.541 0.002074

Kruppel-like factor 4 (gut) 9314 1.85 3.287 0.003364

COMM domain containing 5 /// COMM domain containing 28991 1.85 3.229 0.00408

5 basic leucine zipper nuclear factor 1 (JEM-1) 8548 1.84 2.754 0.012031 zinc finger protein 554 115196 1.81 2.758 0.011728

GULP, engulfment adaptor PTB domain containing 1 51454 1.81 2.536 0.018834 zinc finger protein 639 51193 1.8 3.27 0.003526

MRE11 meiotic recombination 11 homolog A (S. 4361 1.8 2.397 0.029186 cerevisiae)

Interferon-induced protein 44 10561 1.8 2.266 0.036778 dual specificity phosphatase 10 11221 1.8 2.441 0.02345 deoxyribonuclease I 1773 1.8 2.36 0.029046 solute carrier family 19 (thiamine transporter), member 2 10560 1.79 3.649 0.001417 nudix (nucleoside diphosphate linked moiety X)-type 83594 1.78 2.626 0.016353 motif 12 tetraspanin 15 23555 1.77 4.566 0.000158 hypothetical protein MGC52057 130574 1.77 2.671 0.014235 hypothetical protein FLJ20035 55601 1.77 2.844 0.012057

COBW domain containing 1 /// COBW domain containing 150472 /// 1.77 2.438 0.02557

2 /// dopamine responsive protein 220869 ///

55871 ubiquitously transcribed tetratricopeptide repeat, X 7403 1.76 2.635 0.015912 chromosome

Similar to Zinc finger protein 492 388760 1.76 2.748 0.012339 claspin homolog (Xenopus laevis) 63967 1.76 2.351 0.030435

AF464140 163590 1.76 3.181 0.004502 hemochromatosis 3077 1.74 2.634 0.015552

GTPase, IMAP family member 2 26157 1.73 2.405 0.027051 coiled-coil domain containing 2 80173 1.72 2.531 0.020341 hypothetical protein MGC19764 162394 1.71 2.456 0.022875 chromosome 14 open reading frame 105 55195 1.71 2.716 0.012682

Rho GTPase activating protein 26 23092 1.7 2.631 0.016031 homer homolog 2 (Drosophila) 9455 1.7 2.482 0.02381

KIAA0701 protein 23074 1.69 3.096 0.005993

Histamine N-methyltransferase 3176 1.69 2.741 0.012914 melanocortin 4 receptor 4160 1.68 2.583 0.016986

KIAA1333 55632 1.68 3.119 0.005114 solute carrier family 4, sodium bicarbonate cotransporter, 8671 1.67 2.587 0.016897 member 4 v-jun sarcoma virus 17 oncogene homolog (avian) 3725 1.66 4.697 0.000111 retinol dehydrogenase 10 (all-trans) 157506 1.66 2.644 0.016941 mitogen-activated protein kinase associated protein 1 79109 1.65 2.565 0.020635 histamine N-methyltransferase 3176 1.65 2.83 0.009752 etoposide induced 2.4 mRNA 9538 1.64 2.646 0.015223 solute carrier family 35, member F5 80255 1.63 3.177 0.005208 chromosome 7 open reading frame 6 219285 1.63 2.567 0.018428 amyloid beta (A4) precursor protein (protease nexin-II, 351 1.63 2.726 0.012651

Alzheimer disease) tropomyosin 1 (alpha) 7168 1.62 2.726 0.013365 hypothetical protein LOC116068 116068 1.61 2.759 0.012049

Potassium inwardly-rectifying channel, subfamily J, 3763 1.6 2.789 0.010706 member 6

KIAA0433 protein 23262 1.6 2.766 0.013009

Decay accelerating factor for complement (CD55, 1604 1.6 2.671 0.014251

Cromer blood group system) endosulfine alpha 2029 1.58 2.814 0.010801 x 009 protein 56986 1.57 2.729 0.012411

RAB43, member RAS oncogene family 339122 1.57 2.898 0.00839

Kruppel-like factor 3 (basic) 51274 1.57 3.231 0.004905 salvador homolog 1 (Drosophila) 60485 1.56 3.072 0.006495 sterol O-acyltransferase (acyl-Coenzyme A: cholesterol 6646 1.55 2.999 0.007079 acyltransferase) 1 poly (ADP-ribose) polymerase family, member 10 84875 1.55 2.919 0.008234 chromosome 9 open reading frame 64 84267 1.55 3.236 0.003801 zinc finger protein 639 51193 1.54 2.908 0.008231 interferon induced with helicase C domain 1 64135 1.54 2.996 0.006998 CCR4-NOT transcription complex, subunit 6-like 246175 1.54 3.053 0.006269 nuclear receptor binding factor 2 29982 1.53 3.391 0.002628

DKFZP564J0863 protein 25923 1.53 2.943 0.007591 numb homolog (Drosophila) 8650 1.52 3.257 0.003616 nucleoporin 160kDa 23279 1.52 2.784 0.012851

Ku70-binding protein 3 91419 1.52 3.09 0.005398

UDP-N-acetyl-alpha-D-galactosamine:polypeptide N- 2590 1.5 3.113 0.006841 acetylgalactosaminyltransferase 2 (GalNAc-T2)

Chromosome 14 open reading frame 126 112487 1.46 3.452 0.002286 poly(A) polymerase alpha 10914 1.45 3.397 0.002947 tight junction protein 1 (zona occludens 1) 7082 1.42 3.707 0.001491 cornichon homolog (Drosophila) 10175 1.42 3.916 0.000744 dipeptidylpeptidase 8 54878 1.41 3.548 0.002131

Supplemental table 2. Genes downregulated in tumors containing phosphorylated

STAT3 and phosphorylated STAT5 compared to tumors with only phosphorylated

STAT3.

gene name Gene ID fold t statistic P value

change

Hypothetical protein MGC15396 91369 -18.12 -2.692 0.01344

NADH dehydrogenase (ubiquinone) Fe-S protein 7, 374291 -5.13 -2.156 0.042457

20kDa (NADH-coenzyme Q reductase) hypothetical protein MGC34732 220047 -5.07 -2.273 0.034003

FERM, RhoGEF (ARHGEF) and pleckstrin domain 10160 -4.42 -2.141 0.043622 protein 1 (chondrocyte-derived)

Hypothetical protein LOC284412 284412 -4.05 -2.115 0.047995 leucine rich repeat containing 2 79442 -3.74 -2.201 0.041801 protein kinase C binding protein 1 23613 -3.38 -2.404 0.029583

EMI domain containing 2 136227 -3.23 -2.448 0.022817

Tripartite motif-containing 5 85363 -2.42 -2.143 0.048969 enolase 2 (gamma, neuronal) 2026 -2.19 -2.599 0.02232 serine arginine-rich pre-mRNA splicing factor SR- 58506 -2.18 -3.363 0.003889

A1 regulatory factor X, 2 (influences HLA class II 5990 -2.05 -2.299 0.03555 expression) homeo box D9 3235 -2.02 -2.187 0.043673

DNA segment on chromosome X (unique) 9879 8270 -2.02 -2.45 0.033725 expressed sequence

Nedd4 binding protein 1 9683 -2 -2.26 0.048235 Leucine-rich repeat LGI family, member 4 163175 -1.99 -2.239 0.044569 adaptor-related protein complex 2, alpha 1 subunit 160 -1.98 -3.236 0.004649 collagen, type XXV, alpha 1 /// collagen, type XXV, 84570 -1.96 -2.393 0.03222 alpha 1 protein kinase C binding protein 1 23613 -1.89 -2.714 0.019042

Tubby like protein 4 56995 -1.88 -2.289 0.039825 tripartite motif-containing 55 84675 -1.86 -3.038 0.00694 glycophorin E 2996 -1.86 -2.448 0.02352 sterile alpha and TIR motif containing 1 23098 -1.83 -2.843 0.011391 protein kinase C binding protein 1 23613 -1.82 -2.53 0.027141

G protein-coupled receptor 24 2847 -1.82 -2.512 0.024749 casein kinase 1, gamma 1 53944 -1.81 -2.834 0.01019

KIAA0703 gene product 9914 -1.8 -2.798 0.013754

RNA binding motif protein 8A 9939 -1.78 -2.716 0.013975

HLA-B associated transcript 5 7920 -1.78 -3.348 0.003356 tubby like protein 4 56995 -1.74 -2.442 0.033991

Microtubule associated monoxygenase, calponin 57553 -1.74 -2.325 0.042592 and LIM domain containing 3 carboxypeptidase X (M14 family), member 2 119587 -1.73 -2.492 0.023129 zinc finger protein 3 (A8-51) 7551 -1.68 -2.655 0.018759

Signal sequence receptor, alpha (translocon- 6745 -1.67 -3.289 0.00462 associated protein alpha) zinc ribbon domain containing, 1 30834 -1.65 -2.837 0.009878

Stereocilin 161497 -1.65 -3.045 0.007869 protein kinase C binding protein 1 23613 -1.64 -2.744 0.017568 stromal interaction molecule 1 6786 -1.63 -2.849 0.015737 signal transducer and activator of transcription 6, 6778 -1.63 -2.657 0.018722 interleukin-4 induced villin 2 (ezrin) 7430 -1.59 -2.855 0.011415 tubulin-specific chaperone e 6905 -1.59 -3.412 0.00348

LOC440526 440526 -1.56 -2.889 0.013482 leukocyte receptor cluster (LRC) member 4 79143 -1.56 -2.89 0.012677 villin 2 (ezrin) 7430 -1.45 -3.486 0.002757

Supplemental table 3. Normalized mRNA expression of CIS, SOCS3, and BCL6 in the breast cancers stained for STAT3 and STAT5 phosphorylation, grouped by phosphorylation pattern. Expression data are derived from microarray-based quantitation.

Tumor CIS SOCS3 BCL6 STAT activation B10 93.36 545.59 71.54 No STAT 3 or 5 B28 172.4 405.05 28.58 No STAT 3 or 5 B30 183.34 537.88 64.25 No STAT 3 or 5 B37 103.94 121.78 175.25 No STAT 3 or 5 B39 167.64 421.52 138.98 No STAT 3 or 5 B41 124.71 200.42 59.54 No STAT 3 or 5 B52 14.69 418.47 101.83 No STAT 3 or 5 B53 45.23 283.6 67.43 No STAT 3 or 5 B63 70.97 399.02 79.43 No STAT 3 or 5 B78 150.31 684.52 144.76 No STAT 3 or 5 B8 232.24 177.17 84.03 No STAT 3 or 5 B89 238.86 801.69 92.99 No STAT 3 or 5 B90 116.06 440.75 157.08 No STAT 3 or 5 B92 44.66 463.57 160.28 No STAT 3 or 5 B94 171.56 1316.78 90.05 No STAT 3 or 5 B96 54.11 294.75 97.09 No STAT 3 or 5 B14 96.72 1126.17 23.95 STAT 3 only B16 70.47 891.78 48.29 STAT 3 only B17 271.85 369.31 23.44 STAT 3 only B18 183.96 681.13 135.09 STAT 3 only B21 55.67 488.92 54.75 STAT 3 only B24 277.93 641.06 369.22 STAT 3 only B25 85.34 312.27 19.8 STAT 3 only B33 1.24 451.44 73.45 STAT 3 only B34 248.23 482.01 52.37 STAT 3 only B35 41.72 1031.74 30.59 STAT 3 only B38 40.76 755.23 70.92 STAT 3 only B4 103.42 336.53 76.96 STAT 3 only B43 328.52 590.1 303.72 STAT 3 only B47 86.13 391.21 107.43 STAT 3 only B50 275.86 82.81 34.6 STAT 3 only B55 28.37 228.05 98.48 STAT 3 only B57 70.3 324.89 81.03 STAT 3 only B61 238.25 124.85 41.41 STAT 3 only B68 137.56 449.43 36.38 STAT 3 only B70 125.86 651.36 49.11 STAT 3 only B71 291.14 493.59 86.57 STAT 3 only B74 83.22 652.27 64.12 STAT 3 only B77 244 237 39.73 STAT 3 only B82 497.59 422.48 109.66 STAT 3 only B84 44.89 163.19 113.57 STAT 3 only B95 36.6 182.11 219.52 STAT 3 only B98 164.11 407.6 103.53 STAT 3 only B13 199.15 274.46 64.46 STAT 5 only B22 294.24 907.77 47.45 STAT 5 only B76 241.57 178.39 90.39 STAT 5 only B81 96.63 67.39 42.54 STAT 5 only B97 263.94 1714.86 763.04 STAT 5 only B1 149.44 342.53 821.45 STAT 3 and 5 B11 96.91 1236.54 108.13 STAT 3 and 5 B12 47.22 510.58 152.81 STAT 3 and 5 B15 191.24 1231.31 280.29 STAT 3 and 5 B2 43.24 393.69 132.51 STAT 3 and 5 B29 371.35 256.83 58.92 STAT 3 and 5 B3 74.42 551.08 460.11 STAT 3 and 5 B31 139.86 387.73 313.86 STAT 3 and 5 B36 244.3 461.74 69.2 STAT 3 and 5 B40 182.62 326.76 166.06 STAT 3 and 5 B45 152.9 375.57 58.9 STAT 3 and 5 B5 184.92 354.37 99.11 STAT 3 and 5 B65 66.13 862.13 47.56 STAT 3 and 5 B66 106.53 230.16 112.06 STAT 3 and 5 B67 299.07 809.43 47.79 STAT 3 and 5 B7 98.98 548.74 434.43 STAT 3 and 5 B79 86.45 365.6 111.95 STAT 3 and 5 B80 89.73 175.43 80.24 STAT 3 and 5 B85 169.98 1366.87 113.27 STAT 3 and 5 B86 305.64 613.44 235.44 STAT 3 and 5

Mean expression: CIS SOCS3 BCL6 124.01 ± 67.91 469.54 ± 287.95 100.82 ± 42.26 No STAT 3 or 5 152.95 ± 119.55 480.32 ± 263.40 91.40 ± 83.12 STAT 3 only 219.11 ± 76.74 628.57 ± 689.38 201.58 ± 314.43 STAT 5 only 155.05 ± 91.19 570.03 ± 351.52 195.20 ± 191.43 STAT 3 and 5 Supplemental table 4. Primers used for real-time RT-PCR

Gene Forward primer Reverse primer

BCL6 CTGCAGATGGAGCATGTTGT TCTTCACGAGGAGGCTTGAT

CIS CTGCTGTGCATAGCCAAGAC GTGCCTTCTGGCATCTTCTG

GAPDH AATCCCATCACCATCTTCCA TGGACTCCACGACGTACTCA

SOCS3 TCAAGACCTTCAGCTCCAAG TGACGCTGAGCGTGAAGAAG

KLF4 GTTCCCATCTCAAGGCACAC ACGGTAGTGCCTGGTCAGTT

ANKRD40 AGGTGCAGAAACTGGTGGAG TGGACTGGCATTTCTCCTTT

AREG TGGTGCTGTCGCTCTTGATA TCACGCTTCCCAGAGTAGGT

BAT5 TCAACCGGGTTAAGAAGCTG CACAGAGCCTGGATACAGCA

CSNK1G1 TATAATGCCATGGTGCTGGA TGCACGTATTCCATTCGAGA

ETV7 GGAGCGCTCAAGACAGAAAG TGCCACAGGGCTTATAGGAG

NBRF2 GTCGAGCTCCCTTGCAGTC GCTCGTCTGCTCTGTTGATG

PANX1 CAGAGCGAGTCTGGAAACCT GGTACAGGAGGATCGCAAAG

PRKCBP1 CCCTCCACATTCTTCCAATG TCAACAGGGTCTGTGGTGAG

RAB43 ACCATGAAGACGCTGGAGAT GCTCCTCTTGGTGATGTCGT

SAMD9 GGTTGCAGTGGGTGAATAGG AAGTTGCTTTGCCATTCTGA

TLR3 AACTGGATATCTTTGCCAATTCA TTGTTCAGAAAGAGGCCAAA

TSPAN15 GCGCTTCTCCTACCTCTGG TATTTCTGCCGCTCAACCTC

VIL2 GAACAGACCTTTGGCTTGGA CACTCCAAGGAAAGCCAATC

Supplemental figure 1

a b P-STAT5 P-STAT5

STAT5 STAT5

Prolactin: - + EGF: - +

BCL6 BCL6 1.2 1.2 1 1 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0 0 Relative mRNA expression untreated prolactin Relative mRNA expression untx EGF

c P-STAT3 d P-STAT3

STAT3 STAT3

LIF: - + OSM: - +

BCL6 BCL6 2 2.5

1.5 2 1.5 1 1 0.5 0.5

0 0 Relative mRNA expression mRNA Relative Relative mRNA expression untreated LIF untreated OSM

Supplemental figure 1. STAT5 and STAT3 oppositely regulate BCL6. SK-BR-3 cells were stimulated with prolactin (a), EGF (b), LIF (c), or OSM (d) for 15 minutes. STAT5 or STAT3 phosphorylation was analyzed by immunoblot with the indicated antibodies

(top panels). SK-BR-3 cells were stimulated with prolactin (a), EGF (b), LIF (c), or OSM

(d) for 90 minutes. BCL6 mRNA expression was analyzed by quantitative RT-PCR

(bottom panels).

Supplemental figure 2.

a b V 3i STAT5 STAT3 STAT3 STAT5 actin tubulin siC si5a/5b

BCL6 BCL6 3 1.2 untreated untreated LIF 1 2.5 prolactin 0.8 2 0.6 1.5 0.4 1 0.2 0.5 0 0

siC si5a/5b Relative mRNA expression Relative mRNA expression pRS pRS-STAT3i

Supplemental figure 2. STAT5 and STAT3 are necessary for prolactin and LIF

modulation of BCL6 expression. A. SK-BR-3 cells transfected with siRNA to STAT5a

and STAT5b (si5a/5b) or control siRNA (siC) were analyzed by immunoblot with the

indicated antibodies (top panel), or were stimulated with prolactin for 90 minutes and

BCL6 mRNA expression was analyzed by qPCR (bottom panel). B. SK-BR-3 cells were infected with pRetroSuper-STAT3i (pRS-STAT3i) or control vector (pRS) and analyzed by immunoblot for the indicated antibodies (top panel), or were stimulated with

LIF for 90 minutes and BCL6 mRNA expression was analyzed by qPCR (bottom panel). Supplemental figure 3

a b

P-STAT5 1.2

1 P-STAT3 0.8 STAT5 0.6 0.4 STAT3 0.2 BCL6Relative expression 0 Prolactin: - + - + untreated prolactin LIF prolactin/LIF LIF: - - + +

Supplemental figure 3. STAT5 is dominant over constititive and induced STAT3 activation. MDA-MB-468 cells were stimulated with prolactin and LIF, separately and

simultaneously for 15 minutes and analyzed by immunoblot (a) or 90 minutes and BCL6

mRNA expression was analyzed by qPCR (b).

Supplemental figure 4.

SOCS3 14 12 10 8 6 4 2 0 Relative mRNA expression vector STAT5a1*6 vector STAT5a1*6 Pool A Pool B

Supplemental figure 4. Activated STAT5 upregulates SOCS3 expression. MDA-MB-

468 cells stably expressing STAT5a1*6 (pool A and pool B) were analyzed for SOCS3 expression by quantitative RT-PCR normalized to GAPDH. Supplemental figure 5.

a 120 vector 100 STAT5a1*6 80

60

40 % viability 20

0 DMSO 1 2 3 4 5 6 7 uM paclitaxel

b 120 vector

100 STAT5a1*6 80

60

% viability 40

20

0 0 0.25 1 5 uM vinorelbine

Supplemental figure 5. Cells containing activation of both STAT5 and STAT3 are more sensitive to chemotherapy then cells with only STAT3 activation. MDA-MB-468 cells stably expressing STAT5a1*6 were treated with vehicle or the indicated concentrations of paclitaxel (a) or vinorelbine (b) for 48 hours. Viable cells were quantitated and normalized to each vehicle treated control. Similar results were obtained using two independent stable pools of cells.