1. Legends for supplementary figures Fig s1. A: Western blot showing the suppression of SRp20 expression by Dox induction of SRp20 siRNAs in SKOV3 sublines. B: Cell growth curve. Shown are the results of three independent experiments. Error bars represent standard error. C: Left panel, sample micrographs of Hoechst 33342-stained nuclei of SKOV3 subline cells. Arrow indicates the typical apoptotic cells. Right panel, Quantitation of apoptotic cells. Fig s2. A: Western blot showing the suppression of SRp20 expression by Dox induction of SRp20 siRNAs in IGROV1 sublines. B: Cell growth curve of IGROV1 sublines. C: Left panel, sample micrographs of Hoechst 33342-stained nuclei of IGROV1 subline cells. Arrow indicates the typical apoptotic cells. Right panel, Quantitation of apoptotic cells.

2. Dox SKOV3 β-actin SRp20 SRp20si1SRp20si2 - + LUCsi - + Fig s1 A B C SKOV3/LUCsi SKOV3/SRp20si1 SKOV3/SRp20si2 Without DoxWithDox % Knockdown 6791

3. SRp20si1SRp20si2LUCsi - + Dox - + β-actin SRp20 IGROV1 Fig s2 A B C Without DoxWith Dox IGROV1/LUCsi IGROV1/SRp20si1 IGROV1/SRp20si2 % Knockdown 4779

4. † Evaluable cases require at least two satisfactory cores with staining for either PTB or SRp20. Disease Status Satisfactory Cores per Case Evaluable Cases † Total Cases Histologic Subtype for Evaluable Cases 0123MucinousSerousClear CellEndometrioid Poorly Differentiated PTB staining Benign12131431742152000 Borderline/LMP012183149612523010 Invasive12115667702693002 Total1327439013317366343012 SRp20 staining Benign23115384271000 Borderline/LMP2141530456122 010 Invasive2465864702592802 Total2729269111717354322812 Table s1. Distribution of Evaluable and Total Cases by Disease Status, Number of Satisfactory Cores and Histologic Subtype in the Disease Status TMA Stained for PTB or SRp20.

5. Disease status PTB †SRp20 ‡ All Negative Mixed All Positive Total All Negative Mixed All Positive Total Benign7 (46.7)5 (33.3)3 (20.0)151 (14.3)3 (42.9) 7 Borderline/LMP8 (32.0)7 (28.0)10 (40.0)250 (0)9 (40.9)13 (59.1)22 Invasive2 (7.7)5 (19.2)19 (73.1)260 (0)2 (8.0)23 (92.0)25 Total17 32661143954 Table s2. Differential expression of PTB or SRp20 in the mucinous ovarian tumors in the Disease Status TMA Percentage within each staining category is provided in parentheses. Statistical significance was evaluated using Fisher’s exact test for data in 2 x 2 tables [43]; and the Mehta and Patel version of Fisher’s exact test for data in R x C tables [44]. † p=0.0074 for overall test; p=0.0015 for benign vs. invasive; p>0.05 for benign vs. borderline/LMP; p=0.036 for borderline/LMP vs. invasive. ‡ p=0.0036 for overall test; p=0.012 for benign vs. invasive; p>0.05 for benign vs. borderline/LMP; p=0.014 for borderline/LMP vs. invasive.

6. Table s3. Distribution of Evaluable and Total Cases by Tumor Stage, Number of Satisfactory Cores and Histologic Subtype in the Tumor Stage TMA Stained for PTB or SRp20 † Evaluable cases require at least two satisfactory cores with staining for either PTB or SRp20. Tumor Stage Satisfactory Cores per Case Evaluable Cases † Total Cases Histologic Subtype for Evaluable Cases 0123EndometrioidSerous Mixed Epithelial PTB staining Stage I00123446 27154 Stage II03623293210190 Stage III00104757 26292 Stage IV121126374013231 Total153913016917576867 SRp20 staining Stage I141328414625124 Stage II121019293210190 Stage III00124557 26292 Stage IV151222344012211 Total3114711416117573817

7. Categorized stage PTB †SRp20 ‡ LowHighTotalLowHighTotal Early stage (I+II)50 (66.7%)25 (33.3%)7542 (60.0%)28 (40.0%)70 Advanced stage (III+IV)45 (47.9%)49 (52.1%)9432 (35.2%)59 (64.8%)91 Total95741697487161 Table s4. Intensity of PTB or SRp20 staining in the Ovarian Cancer Stage TMA Statistical significance was evaluated using Fisher’s Exact test [43]. Staining intensity was categorized as low (score<2.5) or high (score  2.5). † p=0.019 for comparison of early stage vs. advanced stage. ‡ p=0.002 for comparison of early stage vs. advanced stage.