Results
The evaluations of the paper, figure by figure. Each chart is drawn from the source data of its panel, and every file downloads as it is. The sections and saved results behind Figures 2 to 6 open in the data explorers; your own predictions go under Analyze data.
Reproducible-signal correlation (RSC) avoids overstating and understating prediction quality
In HER2ST, a class-mean baseline that assigns identical expression to every spot of a region reaches a whole-section Pearson r of 0.111, above the median of 11 published methods (0.108; maximum 0.144). In the colorectal cancer data, the observed split-half reliability implies that even an ideal prediction matching the underlying expression would reach a correlation with measured RNA expression of 1.00 at the broadest scale but only 0.44 to 0.57 at the finest, while its RSC stays near 1.
Fig. 1b Pitfall of whole-section correlation
Fig. 1c Noise correction across scales
How it was computed. Fig. 1b, Methods “Whole-section correlation” and “Class-mean baseline”. Fig. 1c, Methods “Expected expression and the mean of the halves”: the measured counts are taken as Poisson rates, the expected expression is scored as the prediction, and Pearson r with measured RNA expression follows from equation (2) with the split-half reliability of the measured counts. Panels a and d, an overview of RSC and a summary of Figs. 2–5, are in the figure on the home page.
Evaluation within tissue regions reveals whole-section correlation overstates prediction quality
Normalized pairwise accuracy of 11 published methods across 785 genes in HER2ST (8 patients) runs from 0% for a majority-order baseline to 100% for split-half agreement. The median falls from 28.5% on unmatched spot pairs to 6.7% on pairs matched for total transcript count and expression profile (Holm-adjusted P = 0.023), and stays at 6.6% for matched pairs in the same annotated region. The class-mean baseline scores 6.8% on matched pairs but 1.5% within a region, where each of the 11 methods predicts a positive fraction of the spot-to-spot differences.
Rankings by whole-section correlation agree with rankings on unmatched pairs (Kendall's τb = 0.818) but are nearly unrelated to rankings within regions (τb = 0.091), and the top-ranked method shifts from EGNv2 to DeepSpaCE. For FASN, Hist2ST predictions correlate with measured RNA at Spearman ρ = 0.534 across all spots of a section but ρ = 0.068 among spots within regions.
How it was computed. strsc her2 computes normalized pairwise accuracy on unmatched, matched and within-region spot pairs (Methods “Evaluation between and within tissue regions”); the same calculation runs in the browser under Pairwise accuracy.
Explore: HER2ST cohort (Fig. 2a–c, g–i) · HER2ST section B1 (Fig. 2f)
Reproducible-signal correlation (RSC) reveals spot-level methods mainly capture coarse tissue structure
In the Visium HD colorectal cancer sections, mean RSC of Ridge–Phikon predictions of 1,000 genes in 32-µm bins falls from 0.800 at 4,096 µm and above to 0.298 below 128 µm, and the decline persists in 22 of 24 combinations of patient and bin size from 32 to 512 µm. In nine Xenium samples of breast, pancreatic and lung cancer, 10 of the 11 spot-level models have lower RSC at the finest than at the broadest scale in all nine samples.
Across 70 sections from 45 patients in the nine tasks of HEST-Benchmark, Ridge–Phikon-v2 is lower at the finest scale in 44 of 45 patients (sign-flip P < 10−6). Pathology foundation models raise RSC at every scale, yet the drop from the broadest to the finest scale stays between 0.31 and 0.34 for all five image encoders. Trained on three spatial blocks of a section to predict the fourth, Ridge–Phikon-v2 rises in fine-scale RSC from 0.152 to 0.219.
Fig. 3a RSC across spatial scales, 32-µm grid
Fig. 3b Tissue composition and sampling noise across bin sizes
Fig. 3c RSC by spatial scale and bin size
Fig. 3d 11 spot-level models in nine Xenium samples
Fig. 3e Image encoders in HEST-Benchmark
Fig. 3f Cross-patient and within-section training
| Readout | Within-section | Cross-patient | Difference (95% CI) | Patients higher | Sign-flip P |
|---|---|---|---|---|---|
| Broadest | 0.632 | 0.444 | 0.187 (0.161 to 0.215) | 44 of 45 | 5 × 10⁻⁷ |
| Broad | 0.350 | 0.257 | 0.094 (0.070 to 0.118) | 41 of 45 | 5 × 10⁻⁷ |
| Mid | 0.280 | 0.192 | 0.088 (0.066 to 0.111) | 39 of 45 | 5 × 10⁻⁷ |
| Fine | 0.231 | 0.167 | 0.064 (0.041 to 0.088) | 33 of 45 | 4 × 10⁻⁶ |
| Finest | 0.207 | 0.138 | 0.070 (0.050 to 0.090) | 41 of 45 | 5 × 10⁻⁷ |
| Fine scale (mean of Fine and Finest) | 0.219 | 0.152 | 0.067 (0.047 to 0.088) | 38 of 45 | 5 × 10⁻⁷ |
| Broad scale (mean of Broadest and Broad) | 0.491 | 0.350 | 0.141 (0.119 to 0.163) | 44 of 45 | 5 × 10⁻⁷ |
| Whole-section Pearson r | 0.323 | 0.242 | 0.081 (0.063 to 0.101) | 44 of 45 | 5 × 10⁻⁷ |
How it was computed. Fig. 3a–c, Methods “Scales and count transforms” (colorectal cancer bins) and “Aggregation in colorectal cancer”; the toolkit scores physical scales on a regular grid with strsc fourier. Fig. 3d, Methods “Spot-level models in HEST”; strsc hest scores the nine Xenium samples on the 50-gene benchmark panel. Fig. 3e,f, Methods “Evaluation across spatial scales” and “Within-section training”; these HEST-Benchmark analyses belong to the paper and have no toolkit command.
Explore: HEST sample TENX118, spatial scales
Reproducible-signal correlation (RSC) distinguishes a robust single-cell prediction method
Within malignant cells of breast cancer sections profiled by Xenium (5 patients, nine sections), GHIST has the highest RSC at all five scales. Its fine-scale RSC is 0.242, against 0.042 for DeepSpot2Cell and 0.020 for sCellST, with a fine-scale split-half reliability of 0.173.
Across all cells, a class-mean baseline outscores sCellST (fine-scale RSC 0.081 versus 0.036), and averaging the same predictions into 256-µm bins raises fine-scale RSC by 0.14 to 0.17 (GHIST from 0.285 to 0.435). Hotspots defined in one RNA half and scored in the other reach a mean enrichment of 0.976; hotspots predicted by GHIST reach 0.335, those of sCellST 0.101 and those of DeepSpot2Cell −0.064.
How it was computed. python -m strsc.cell_score computes RSC within a cell class, across all cells and in bins, and the proliferation hotspots (Methods “Evaluation within cell classes”).
Explore: Xenium breast cancer cells · all cells in bins · proliferation hotspots
Reproducible-signal correlation (RSC) reveals models locate tertiary lymphoid structures (TLS) yet poorly predict internal expression
Eight TLS-associated genes in kidney and lung cancer Visium sections, each section predicted by Ridge–Phikon-v2 trained on the remaining sections. The predictions separate annotated TLS from immune-infiltrated, tumor and normal spots with an AUROC of 0.93 to 0.99 across sections, above the 0.61 to 0.71 of single-spot measured RNA, but a class-mean baseline reaches 0.99 to 1.00.
Between regions, the class-mean baseline reaches RSCs of 0.73 to 0.83 and Ridge–Phikon-v2 0.59 to 0.79. Within annotated TLS, Ridge–Phikon-v2 reaches only 0.25 to 0.29.
How it was computed. Methods “Evaluation of TLS-associated genes”: each prediction and each RNA half is divided into the mean of its annotated region and the residual from that mean, and RSC is formed between regions, within regions and within TLS.
Explore: External TLS sections (Fig. 5a–f)
Training guided by reproducible-signal correlation (RSC) generally improves method performance
Across the 11 spot-level models in the nine Xenium samples, the pairwise difference loss raises mean fine-scale RSC from 0.194 to 0.205, and the mean over the models rises in all nine samples. On neighboring spot pairs the loss raises fine-scale RSC by 0.009 more than on the same number of randomly paired non-neighboring spots (exact sign-flip P = 0.0039), with a positive mean gain in 9 of the 11 models.
For Ridge–Phikon-v2 in HEST-Benchmark, the loss raises fine-scale RSC by 0.015, 22% of the 0.067 gain obtained from within-section training. The same loss lowers the RSC of Ridge–Phikon-v2 between regions and within TLS, and changes fine-scale RSC little for sCellST and DeepSpot2Cell.
Fig. 6a Pairwise difference loss versus standard training
Fig. 6b Change in RSC by scale
How it was computed. The loss and the model adapters are in strsc.training; predictions after standard training and with the loss are scored as in Fig. 3d (Methods “Training with the pairwise difference loss”). In the browser, Pairwise difference loss trains Ridge with and without the loss on your data.
Fig. 6c,d: the score table opens under Computed results (Score table), and downloads as neighboring-pairs-scores.csv.
Validation of reproducible-signal correlation with simulated and downsampled counts
With the injected patterns as predictions, RSC is highest at the injected scale in 262 of 264 estimable conditions, and a 90° shift of the spatial phase lowers the mean absolute RSC to 0.0012. When the true underlying expression rates are scored as predictions, RSC stays between 0.956 and 1.000 from the broadest to the finest scales, while the correlation with counts drops by the amount that equation (2) gives.
Downsampling the nine Xenium samples to one-eighth of their molecules lowers the fine-scale split-half reliability from 0.416 to 0.247 and whole-section Pearson r from 0.509 to 0.408, in all nine samples, whereas fine-scale RSC changes from 0.337 to 0.386. With ℓg fixed at its value at full depth, fine-scale RSC changes from 0.337 to 0.358.
Extended Data Fig. 1c Expected expression in three datasets
Extended Data Fig. 1d Downsampled counts in HEST
How it was computed. Methods “Tests of the reproducible-signal correlation”. Panels a, b, e and f use three colorectal patients with Poisson or negative binomial counts at eight bin sizes; they are in the paper, and their source data are not on this site.
The source and license of each dataset are listed with the data explorers and in Supplementary Table 7 of the paper.