**Figure 3. Tumor free survival and tumor histopathology.** (**A**) Kaplan-Meier plot of tumor free survival (TFS). Female athymic nude mice subcutaneously injected in the right flank with NRAS^G12D melanocytes harboring GFP [n=14] or *PREX2* variants (PREX2^WT [n=7], PREX2^G844D[n=14], or PREX2^Q1430* [n=8]) were monitored every other day for tumor growth. Cox proportional hazards regression model (CPH) with *a priori* Bonferroni adjusted significance threshold = .0125. GFP vs. PREX2^G844D, uncorrected *p* = .847 (Bonferroni corrected *p* > .99); GFP vs. PREX2^Q1430*, uncorrected *p* = .944 (Bonferroni corrected *p* > .99); PREX2^WT vs. PREX2^G844D, uncorrected *p* = .652 (Bonferroni corrected *p* > .99); PREX2^WT vs. PREX2^Q1430*, uncorrected *p* = .529 (Bonferroni corrected *p* > .99). Median TFS for all groups = 1 week. (**B**-**E**) Representative histological section of (**B**) GFP xenograft, (**C**) PREX2^WT xenograft, (**D**) PREX2^G844D xenograft, and (**E**) PREX2^Q1430* xenograft stained with hematoxylin and eosin. Access [full size image][1] and [svg file][2] made with [Inkscape][3], version 0.91. [Figure 3A][4] was generated with this [R script][5] and will call the [data][6] directly from the OSF. Representative histopathology images for are these files: (**B**) GFP; [713#1-2.jpg][7], (**C**) PREX2^WT; [721#1-1.jpg][8], (**D**) PREX2^G844D; [730#2-1.jpg][9], (**E**) PREX2^Q1430*; [728#2-4.jpg][10]. All histopathology images can be found [here][11]. <br> **Figure 3 - figure supplement 1.** Table summarizing incidence rates for both Berger et al. and the current study by week after injection with NRAS^G12D melanocytes harboring *PREX2* isoforms. Access the [full size image][12] and [R script][13] used to generate this figure. <br> **Figure 4. Tumor growth.** Female athymic nude mice were subcutaneously injected in the right flank with NRAS^G12D melanocytes expressing GFP or PREX2 isoforms (PREX2^WT, PREX2^G844D, or PREX2^Q1430*). Following tumor detection, caliper measurements were taken every 7 days and used to calculate tumor volume. (**A**) Line graph of first 6 tumor volume measurements of mice before tumors began to reach 1.5cm³ and mice were euthanized (y-axis is natural log scale). Two mice (one GFP and one PREX2^G844D) are excluded because there were euthanized during the reported timeframe. Means reported and error bars represent SD. Number of mice: GFP [n=13], PREX2^WT [n=7], PREX2^G844D [n=13], and PREX2^Q1430* [n=8]. (**B**) The first 6 tumor volume measurements were used to calculate area under the curve (AUC) for each mouse. Box and whisker plot with median represented as the line through the box, individual animal AUC values represented as dots, and whiskers representing values within 1.5 IQR of the first and third quartile (y-axis is natural log scale). Number of mice: GFP [n=13], PREX2^WT [n=7], PREX2^G844D [n=13], and PREX2^Q1430* [n=8]. One-way ANOVA on AUC (natural log-transformed); *F*(3,37) = 2.411, *p* = .0824, ηP2 = 0.164, 90% CI [0, 0.290]. Four contrasts were performed: GFP vs. PREX2^G844D: *t*(37) = 1.217, uncorrected *p* = .231, Bonferroni corrected *p* = .925, Cohen’s *d* = 0.477, 95% CI [-0.308, 1.253]; GFP vs. PREX2^Q1430*: *t*(37) = 2.568, uncorrected *p* = .014, Bonferroni corrected *p* = .058, Cohen’s *d* = 1.154, 95% CI [0.188, 2.094]; PREX2^WT vs. PREX2^G844D: *t*(37) = 0.752, uncorrected *p* = .457, Bonferroni corrected *p* > .99, Cohen’s *d* = 0.352, 95% CI [-0.578, 1.274]; PREX2^WT vs. PREX2^Q1430*: *t*(37) = 1.988, uncorrected *p* = .054, Bonferroni corrected *p* = .217, Cohen’s *d* = 1.029, 95% CI [-0.076, 2.099]. Access the [full size image][14] and [R script][15] used to generate this figure. This script will call the [data][16] directly from the OSF. <br> **Figure 4 - figure supplement 1. Individual tumor xenografts.** This is the same experiment as in Figure 4, but with the tumor volume plotted for each animal rather than averages. Female athymic nude mice subcutaneously injected in the right flank with NRAS^G12D melanocytes expressing GFP [n=14] or PREX2 isoforms (PREX2^WT [n=7], PREX2^G844D [n=14], or PREX2^Q1430* [n=8]). Following tumor detection, tumor measurements were taken every 7 days and used to calculate tumor volume. (**A**-**D**) Growth curves (natural log scale) for each mouse in each condition is shown. Mice were euthanized when tumor volume reached 1.5cm³. Access the [full size image][17] and [R script][18] used to generate this figure. This script will call the [data][19] directly from the OSF. <br> ---------- [Statistical Analyses component][20] contains R scripts that were used for the analysis. <br> ---------- [Additional exploratory figures][21] not included in the manuscript were also generated to provide alternative visualization of the data collected. [1]: https://osf.io/j6hqg/ [2]: https://osf.io/xaqxm/ [3]: https://inkscape.org/en/ [4]: https://osf.io/rkjyv/ [5]: https://osf.io/4sxhc/ [6]: https://osf.io/d7y5s/ [7]: https://osf.io/w2zbj/ [8]: https://osf.io/52p68/ [9]: https://osf.io/tvyrf/ [10]: https://osf.io/dmt83/ [11]: https://osf.io/jvra5/files/ [12]: https://osf.io/f259h/ [13]: https://osf.io/k3em9/ [14]: https://osf.io/c9r2j/ [15]: https://osf.io/ykauz/ [16]: https://osf.io/52wz3/ [17]: https://osf.io/bfywx/ [18]: https://osf.io/3t2fb/ [19]: https://osf.io/52wz3/ [20]: https://osf.io/z9mhg/wiki/home/ [21]: https://osf.io/pqyks/wiki/Additional%20exploratory%20figures/?edit&view&menu