Hakken: Predicting future discoveries to fill the gaps in today's knowledge
Authors: Tarek R. Besold, Uchenna Akujuobi, Pablo Sanchez, Alessandra Toniato, Kana Maruyama, Jihun Choi, Samy Badreddine, Frederick Gifford, Daniel Evans-Yamamoto, Sucheendra K. Palaniappan, Miquel Ferrer, Kae Nagano, Iris Rossell, Tom Joy, Hatem ElShazly, Chrysa Iliopoulou, Christoph Wehner, Thiviyan Thanapalasingam, Susana Nunes, Pedro G. Cotovio, Peter Wurman, Peter Stone, Hiroaki Kitano, Michael Spranger
Organizations: SonyAI, Barcelona, Spain. · SonyAI, Zurich, Switzerland. · SonyAI, Tokyo, Japan. · SonyAI, London, UK. · The Systems Biology Institute, Tokyo, Japan. · SonyAI, New York, NY, USA. · Okinawa Institute of Science and Technology (OIST), Okinawa, Japan.
We present Hakken, a domain-agnostic prediction and explanation system performing knowledge prediction, i.e., growing scientific knowledge by establishing novel relationships, ones that are not limited to the deductive hull of previous knowledge. Hakken uses a transformer-based prediction model built on temporal sequences of knowledge graphs extracted from vast bodies of research publications, fused with an LLM's semantic knowledge, to predict the presence and define the type of as-yet undocumented relationships between scientific concepts. It then calls a model-agnostic explanation framework to provide accompanying information for each prediction that allows scientists to evaluate the suggested new relationship. While general purpose, we demonstrate Hakken's practical capabilities by applying it to the biomedical domain. There, Hakken's prediction model establishes a new benchmark for time-aware multi-label relation prediction, and we show that the model's output stays coherent and informative over extended time spans in historic data. In addition, we scored 1.5 million above-confidence-threshold hypotheses related to aging, qualitatively validated batches of these predictions with biologists and progressed three of them for empirical validation in wet-lab. Two predictions with potentially significant impact in the context of drug discovery and repurposing were confirmed, introducing previously undocumented interactions between TP53 and BAMBI, and between RAF1 and TNF, to biomedical science.
Figures & tables
Figure 1: THiGERLLM for multi-label relation prediction. Given an entity pair (u,v) , the model combines a hierarchical temporal graph encoder with a language model. The graph branch summarizes structural and temporal evidence into compact graph embeddings, which are projected as prefix tokens and injected into the LLM together with publication-derived text. Graph-based and text-based label scores are then combined to produce the final predicted relations, and the resulting probabilities are calibrated to yield confidence scores.
Figure 2: PHELInE providing explanations for THiGERLLM ’s predictions. A surrogate model is trained once (offline) to approximate prediction scores of THiGERLLM . At inference time (online), for each hypothesis—a candidate triple (subject, relation, object)—we enumerate relational paths in the knowledge graph that connect the entities. For each path, we query the surrogate on subgraphs with and without that path to compute sufficiency (how much the path supports the prediction) and necessity (how much removing it weakens the prediction). Paths are ranked by influence and reranked by diversity to produce final explanations.
Model
Precmacro
Recmacro
F1,macro
Precw
Recw
F1,w
nDCGmean
Random
6.08
6.86
3.78
18.21
6.07
8.36
35.20
ComplEx
5.34
8.29
5.80
17.15
19.68
18.15
47.21
KNN
33.00
26.85
28.53
60.93
58.52
59.10
74.59
MLP
39.46
26.81
28.75
66.96
60.19
61.52
86.81
RuleBased
12.81
56.39
19.08
29.43
91.08
42.22
78.98
TNodeEmbed
40.57
27.41
29.17
68.94
62.42
63.47
87.63
Table 1: Baseline comparison for time-aware multi-label relation prediction for a 2020 cut-off. All metrics are reported in percent to improve readability.
Figure 3: Historic validation results for THiGERLLM . First row (a–c): Discovery coverage across disjoint horizons. Each curve reports micro recall for new relations that first appear in each future window. Second row (d–e): Discovery coverage across disjoint horizons. Each curve reports macro recall for new relations that first appear in each future window. Third row (f–g): Stability of prioritization across disjoint horizons. Mean nDCG quantifies whether relations that first appear in a given future window concentrate near the top of the ranked list.
Appendix figures & tables23 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 4: Temporal modeling via hierarchical Transformer with pairwise merging and pairmate-only attention masking.
Figure 5: Token-based injection by replacing <htg> with global node-pair embedding and prepending M temporal graph tokens
Figure 6: Temporal evaluation across historical cut-offs (ranking over all candidates). Mean nDCG computed over the full candidate set (including both transductive and inductive cases). Scores are reported for temporal cut-offs at 1990, 2000, 2010, and 2020.
Figure 7: Benchmark performance of models trained incrementally up to different cutoff years. Rows correspond to training cut-offs at 1990, 2000, 2010, and 2020 (top to bottom). Each model is evaluated on the following decade, except the model trained up to 2020, which is evaluated on data through 2023. Columns show different metrics.
Figure 8: Per-relation-type performance gain of THiGERLLM over THiGER as a function of relation-type test support. Left: For each relation type, the change in Precision, Recall, and F1 is plotted against the number of test facts ( log10 -scaled). Each point represents one relation type. Dashed lines show ordinary least-squares fits on log-scaled support. The inset reports the slope, p-value, and R2 for each metric. Right: Distribution of test-set support across relation types, shown on a log10 scale. This figure illustrates how the relative performance gain of THiGERLLM varies with relation frequency.
Model
Precmacrom
Recmacrom
F1,macrom
Precwm
Recwm
F1,wm
m=1
Random
6.04
4.99
3.19
19.12
5.01
7.34
ComplEx
5.34
4.14
3.95
17.15
9.76
12.29
KNN
33.13
23.54
24.34
61.64
52.16
53.19
MLP
37.51
25.54
26.43
65.50
58.46
57.74
RuleBased
38.92
18.53
19.78
58.37
48.84
47.02
Appendix
Table 2: Baseline comparison for time-aware multi-label relation prediction under a 2020 cut-off using top- m evaluation ( m=1,3,5 ). For each entity pair, only the top- m predicted relation labels are treated as positive predictions. Macro- and weighted precision, recall, and F1 are reported in percent. Unlike threshold-based evaluation, this setting compares models under a fixed prediction budget.
Scenario
Issue
Resolution
Only AFFECTS present (e.g., A affects B @ t1)
No inconsistency; base relation already present.
Do nothing. AFFECTS is kept.
Only INCREASES present (e.g., A increases B @ t1)
Missing the more general parent relation.
Add AFFECTS with same timestamp (t1); keep INCREASES.
Only DECREASES present (e.g., A decreases B @ t2)
Missing the more general parent relation.
Add AFFECTS with same timestamp (t2); keep DECREASES.
Both INCREASES and AFFECTS present (e.g., A affects B @ t1; A increases B @ t1)
No inconsistency; parent + child relation already aligned.
Do nothing. Both are kept.
Both DECREASES and AFFECTS present (e.g., A affects B @ t3; A decreases B @ t3)
No inconsistency; parent + child relation already aligned.
Do nothing. Both are kept.
Both INCREASES and DECREASES present (e.g., A increases B @ t1; A decreases B @ t4)
Mutually contradictory child relations. A general relation (AFFECTS) is missing.
Remove INCREASES and DECREASES , add AFFECTS with the earlier timestamp (t1).
Appendix
Table 3: Examples and rules used to resolve inconsistencies among AFFECTS , INCREASES , and DECREASES .
#
Original relation
Action
Transformed relation
1
INDUCES
keep
–
2
IS_A_BIOMARKER_FOR
keep
–
3
OF
merge into
IS_A_BIOMARKER_FOR
4
INHIBITS
keep
–
5
TREATS
keep
–
6
IS_TREATED_BY
swap (s ↔ o)
TREATS
Appendix
Table 4: Relation-type renaming, merging, or removal based on expert review.
Step
Input hypotheses
Output hypotheses
Notes
prepare
1,543,297
1,524,046
Removes existing graph relations.
filter_topk_entities
1,524,046
2,804
Top-3 filter applied.
Appendix
Table 5: Filtering statistics for hyothesis selection pipeline.
Path length
Count
3
104
4
2,068
5
631
6
1
Appendix
Table 6: Shortest-path-length distribution among final Batch 2 hypotheses.
E1
E2
Relation
Recency E1
Recency E2
MPL
Confidence
SOAT1
STAT3
affects_transcriptional_activity_of
2021
2021
–
0.84183
RAF1
TNF
decreases_expression_of
2021
2011
–
0.83114
TP53
BAMBI
affects_expression_of
2021
2018
–
0.85391
Appendix
Table 7: List of the selected hypotheses for wet-lab validation. E1=entity 1 in the relation, E2=entity 2 in the relation, MPL=minimum path length exisiting between the two entitites.
E1
E2
Relation
Validation Summary
SOAT1
STAT3
affects_transcriptional_activity_of
Denied
RAF1
TNF
decreases_expression_of
Supported
TP53
BAMBI
affects_expression_of
Supported
Appendix
Table 8: List of the selected hypotheses for wet-lab validation. E1=entity 1 in the relation, E2=entity 2 in the relation.
Figure 9: Jess (Simple Western) of STAT3/pSTAT3 under induction of SOAT1. pSTAT3 induction in IL-6 or LDL treated HepG2 lysates at 4 and 24 hours under low serum conditions. HepG2 cells were pre-treated with nevanimibe (0, 0.3, 1 μ M) and then stimulated with IL-6 (100 ng/mL) for 4 or 24 hours. Total STAT3 was detected at the expected molecular weight in all treatment conditions. The induction of pSTAT3 was only observed in the presence of IL-6 and not induced by any of the LDL treatment conditions.
Figure 10: RT-qPCR of STAT3 under SOAT1 induction. Time-dependent STAT3 expression changes in response to LDL and nevanimibe treatment in HepG2 cells (4 and 24 hours, 1% serum). STAT3 expression levels were compared as a percent change relative to the vehicle control baseline (medium only). IL-6 (100 ng/mL) was included as a positive control for STAT3 induction and showed increased expression at both timepoints. Treatment with LDL failed to significantly alter STAT3 expression levels at either timepoint. Nev: + (300 nM), ++ (1000 nM)
Figure 11: TNF expression in THP-1 cells following treatment with RAF1 inhibitors GW5074 and AZ 628. THP-1 cells (8 × 10 4 per well) were treated for 4 hours or 24 hours with 0.2% DMSO (vehicle control), 100 ng/mL LPS (positive control), or the indicated concentrations of GW5074 (+:10 nM, ++: 100 nM, +++: 1000 nM) or AZ 628 (+:30 nM, ++: 300 nM, +++: 3000 nM) RAF1 inhibitors. TNF expression was normalized to ACTB and presented as Log 2 fold change. Each condition represents n=4 biological replicates; bars represent mean ± SEM. Statistically significant differences compared to the vehicle control are indicated (*p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001).
Figure 12: TNF expression in THP-1 cells following GW5074 and ZM336372 treatment (confirmatory assay). THP-1 cells (8 × 10 4 per well) were treated for 4 hours or 24 hours with 0.2% DMSO (vehicle control), 100 ng/mL LPS (positive control), or the indicated concentrations of GW5074 (+:10 nM, ++: 100 nM, +++: 1000 nM) or ZM336372 (+:100 nM, ++: 300 nM, +++: 1000 nM) RAF1 inhibitors. Consistent with the initial Stage 3 assay, a modest increase in normalized TNF expression was observed at 24 hours after treatment with 1000 nM GW5074. Each condition represents n=4 biological replicates; bars represent mean ± SEM. Statistically significant differences compared to the vehicle control are indicated (*p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001).
Figure 13: BAMBI expression changes in response to Nutlin-3 treatment at 24 hours. HepG2 cells were treated with the indicated concentrations of Nutlin-3 for 24 hours. Expression was quantified using the ΔΔ Ct method and normalized to ACTB. Data are presented as percentage change relative to the vehicle control baseline (0.2% DMSO). Three initial seeding densities (1, 2, or 4 × 10 4 cells per well) are indicated by bar colors. Each condition represents n=3–4 biological replicates; bars show mean ± standard error. TGF β 1 (10 ng/mL) was included as a positive control for BAMBI induction. Statistically significant changes compared to the vehicle control are indicated (*p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001).
Figure 14: Time-dependent BAMBI expression changes with Nutlin-3 treatment. HepG2 cells were treated with the indicated concentrations of Nutlin-3 for 8, 16, 24, or 48 hours. BAMBI expression was quantified using the ΔΔ Ct method and normalized to ACTB. Data are shown as percent change relative to the vehicle control baseline (0.2% DMSO). TGF β 1 (10 ng/mL) was included as a positive control for BAMBI induction. Each condition represents n=4 biological replicates; bars show mean ± standard error. The 48-hour TGF β 1 treatment exceeded the y-axis range, with a mean percent change of 214% ( ± 14%). Statistically significant changes compared to the vehicle control are indicated (*p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001).
Equipment/Software Name
Cat No./ID No./Serial No./Version
Vac-Man 96 Vacuum Manifold
A2291
MiniAmp Thermal Cycler
A37834
Quantstudio 6 Flex Real-Time PCR System
4485689
Agilent 50 TS Plate Washer
S/N 2302141D
BioTek Cytation5
S/N 21041316
Gen5 software
3.13.15
Appendix
Table 9: List of equipment used for wet-lab validation.
Hypothesis
Cell Line
Vendor
Catalog No.
Morphology
Tissue
Disease
SOAT1-STAT3
HepG2
ATCC
HB-8065
Epithelial-like
Liver
Hepatocellular carcinoma
TP53-BAMBI
HepG2
ATCC
HB-8065
Epithelial-like
Liver
Hepatocellular carcinoma
RAF1-TNF
THP-1
ATCC
TIB-202
Monocyte
Peripheral blood
Acute monocytic leukemia
Appendix
Table 10: List of cell lines used for wet-lab validation.
Category
Reagent Description
Vendor
Catalog No.
Cell culture
Eagle’s minimum essential medium (EMEM)
ATCC
30-2003
Cell culture
FBS
ATCC
30-2020
Cell culture
Ca 2+ /Mg 2+ free HBSS
Merck (Sigma Aldrich)
H6648
Cell culture
Ca 2+ /Mg 2+ free PBS
Merck (Sigma Aldrich)
D8537
Cell culture
Penicillin-Streptomycin (100x)
Merck (Sigma Aldrich)
P4333
Cell culture
Recombinant Human IL-6
Fisher Scientific
200-06-50UG
Appendix
Table 11: List of reagents used for SOAT1-STAT3 hypothesis validation.
Category
Reagent Description
Vendor
Catalog No.
Cell culture
Eagle’s minimum essential medium (EMEM)
ATCC
30-2003
Cell culture
FBS
ATCC
30-2020
Cell culture
Ca 2+ /Mg 2+ free HBSS
Merck (Sigma Aldrich)
H6648
Cell culture
Ca 2+ /Mg 2+ free PBS
Merck (Sigma Aldrich)
D8537
Cell culture
Penicillin-Streptomycin (100x)
Merck (Sigma Aldrich)
P4333
Cell culture
Transforming growth factor- β 1
R&D systems
240-B-002
Appendix
Table 12: List of reagents used for TP53-BAMBI hypothesis validation.
Category
Reagent Description
Vendor
Catalog No.
Cell culture
RPMI-1640 medium
ATCC
30-2001
Cell culture
FBS
ATCC
30-2020
Cell culture
2-Mercaptoethanol
Fisher
11508916
Cell culture
Ca 2+ /Mg 2+ free HBSS
Merck (Sigma Aldrich)
H6648
Cell culture
Penicillin-Streptomycin (100x)
Merck (Sigma Aldrich)
P4333
Cell culture
Lipopolysaccharides from Escherichia coli O127:B8 (LPS)
Merck
L4516
Appendix
Table 13: List of reagents used for RAF1-TNF hypothesis validation.
Geneva School of Economics and Management, University of Geneva, Geneva, Switzerland · Faculty of Medicine, University of Geneva, Geneva, Switzerland · TU Eindhoven, The Netherlands +2