Molecule guides
Oncology Research Reagents: Peptide Families, Antisera and Kits in the Cancer Catalog
How the cancer topic is organised: which families belong to it, what each reagent is ordered for, and how to match format, species and label chemistry to your assay.
Four distinct roles account for the oncology peptides and antibodies stocked here. Some supply ligands for checkpoints and receptors in immuno-oncology experiments; some act on blood-vessel formation; some calibrate quantitative immunoassays against tumour markers; and some are cleaved by proteases in invasion studies. The cancer topic page gathers the peptide standards, antisera, labelled tracers and kits laboratories buy for this work, arranged by parent molecule. What follows sets out which families the topic contains, why each is ordered, and which reagent format answers which question.
What the cancer topic includes
Grouping reflects experimental application rather than any assertion about what a molecule does clinically. Something qualifies for this topic when the oncology literature treats its parent protein or peptide as an established target, marker or laboratory tool — that covers the checkpoint proteins, controllers of vessel growth, gut hormones with documented mitogenic receptors on cancer cell lines, proteases linked to breakdown of the matrix, and secreted markers by which disease is staged or followed in models. Plenty of families overlap with other topics — somatostatin also features in neuropeptide research, adiponectin in obesity studies. Nothing listed here is a therapy: each product exists strictly for laboratory assays and sanctioned animal studies.
Checkpoint and immuno-oncology reagents
Checkpoint biology accounts for much of what laboratories currently order. Across these families you will find blocking peptides, pieces of extracellular domains, and antisera for staining expression in tumour material:
- PD-1 and PD-L1 — sequences spanning the surface where the two proteins meet, used as immunogens and in competition or binding experiments, together with antisera for scoring stained tumour sections.
- CTLA-4 — the second of the classical checkpoint pathways, available as standards and antibodies for studies of how T cells are co-stimulated.
- TNF and the interleukins — cytokines and their fragments for microenvironment research, doubling as calibration material in multiplex panels.
- Chemokines of the CXCL and CCL families, SDF-1 (CXCL12) included — used where cells are tracked as they migrate or home to secondary sites; few pathways in the spread of tumours have received as much attention as SDF-1 with CXCR4.
Angiogenesis and its peptide inhibitors
Few areas offer as many peptide reagents as this one, and the reason is structural: a number of the body's own inhibitors turn out to be pieces cut from bigger matrix proteins.
- Endostatin — cut from the C-terminus of collagen XVIII, the textbook natural inhibitor of vessel growth, applied in migration and tube-formation work with endothelial cells.
- Anginex — an engineered beta-sheet peptide directed at galectin-1 on activated endothelium, a synthetic tool rather than a natural fragment.
- Vasohibin and PEDF — endothelium-derived negative regulators, supplied as standards and for antibody-based detection.
- Thrombospondin — peptides from the TSP-1 type-1 repeats, including the ABT-510 lineage, which serve as standard positive controls in anti-angiogenic screening.
- Angiopoietin — Ang-1/Ang-2 and Tie2 pathway reagents for vessel-stability studies, overlapping substantially with the cardiovascular topic.
Markers, growth factors and invasion-related families
The remaining families split between markers measured in samples and tools used mechanistically:
- Chromogranin A — the standard secretory marker for neuroendocrine tumours and one of the most frequently ordered assay-kit targets in the topic.
- Gastrin and CCK — reagents for CCK-B/gastrin receptor signalling on gastrointestinal tumour lines, supplied both as full-length peptides and as receptor-selective analogues.
- Bombesin and gastrin-releasing peptide — historically central to autocrine growth loops in small-cell lung carcinoma models and still used in developing GRPR-targeted probes.
- Somatostatin — SSTR subtype pharmacology underpins both neuroendocrine tumour imaging and a substantial literature on antiproliferative effects in cells.
- Survivin and Bcl family peptides — tools for studying apoptosis regulation, including BH3-domain peptides used to probe mitochondrial priming.
- uPAR, cathepsin and autotaxin — the invasion and matrix-remodelling group, with cathepsin substrates normally ordered as fluorogenic labelled peptides.
- Osteopontin and glypican — adhesion and co-receptor families with recognised marker roles, glypican-3 especially in hepatocellular models.
- TGF-β — both tumour suppressor and promoter depending on context, with peptide standards and antisera supporting either side of that literature.
Formats found in the cancer topic
Four product types appear repeatedly across these families. Synthetic peptide standards do most of the work — blocking peptides, receptor ligands and immunogens, typically at ≥95% HPLC purity in microgram-to-milligram fills. Labelled peptides count for more in this topic than in most, since protease assays rely on FRET-paired fluorogenic substrates and biotinylated ligands underpin pull-down experiments. Polyclonal antisera support immunohistochemistry on tumour sections and Western detection. ELISA and EIA kits quantify secreted markers such as chromogranin A or endostatin in plasma and conditioned medium. Pull-downs and immunoprecipitations also consume magnetic beads, while epitope-mapping projects use peptide libraries — overlapping scans across a tumour antigen are a routine request.
Choosing within a family
Three questions dominate. First, fragment or full length: checkpoint work nearly always uses interface fragments rather than an entire ectodomain, and a blocking peptide is validated for absorbing an antibody, not for receptor pharmacology. Second, species: mouse xenograft and syngeneic models call for mouse-sequence reagents, and an antiserum raised against the human sequence cannot be assumed to cross-react — every item declares its species reactivity. Third, compatibility with the assay: a fluorogenic substrate is defined as much by its label pair and quenching chemistry as by its sequence, so verify the excitation and emission profile against your plate reader before ordering.
Handling notes specific to this topic
Most peptides in the cancer topic are small, lyophilised and stable for years when sealed at −20 °C. Two warnings carry extra weight here. Hydrophobic sequences — including several BH3 and thrombospondin-derived peptides — go into solution poorly in aqueous buffer and may require an organic co-solvent; see peptide solubility. And fluorogenic substrates are light-sensitive, so aliquot them under dim light and keep them in amber vials. General practice is covered in the storage guide and the aliquoting guide, with content verification in the COA guide.
Where to look next
Browse the complete cancer topic, or start at the research catalog hub. Related guides include the cardiovascular section, which shares the angiogenesis families, and the assay kit type guide if your question concerns marker quantitation rather than mechanism.
Questions
Are any of these peptides treatments for cancer?
None of them. Every item in this section is a laboratory reagent for in-vitro assays and approved animal research. Some families — endostatin, thrombospondin fragments, somatostatin analogues — do have clinical research histories, but the material catalogued here is not made to pharmaceutical standards.
What is a blocking peptide, and when would I use one?
It is the immunogen sequence against which an antiserum was raised. Pre-incubating the antibody with an excess of it should eliminate specific staining, which serves as the standard specificity control for immunohistochemistry and Western blotting. It is a control reagent rather than a pharmacological tool — the glossary entry on blocking peptides explains further.
For a xenograft study, should reagents be human or mouse sequence?
That depends on the readout. Human-sequence reagents pick up the implanted tumour, while mouse-sequence reagents pick up host stroma, vasculature and immune infiltrate. Since angiogenesis and immune infiltration in a xenograft come from the host, mouse reagents are usually the right choice there even though the tumour itself is human.
Why do protease substrates come as labelled peptides?
Because activity shows up as a change in fluorescence. A fluorogenic substrate places a fluorophore and a quencher on either side of the cleavage site, so that cleavage separates them and signal rises. This makes the label pair as critical as the sequence — match excitation and emission to your instrument. The labelled peptides guide describes the chemistries.
Which markers in this topic are better measured with a kit than with an antibody?
Those secreted into plasma, serum or conditioned medium — chromogranin A, endostatin, osteopontin and several chemokines. An ELISA or EIA kit supplies a matched antibody pair, standards and a validated range, which is quicker and more reproducible than assembling the parts yourself. Antibodies alone remain the choice for tissue localisation and blotting.
How well do BH3 and other hydrophobic peptides hold up in solution?
Less well than typical hydrophilic peptides, and they are harder to dissolve to begin with. Many need DMSO or another organic co-solvent before dilution into aqueous buffer, and they can aggregate on standing. Prepare them fresh where the assay permits, aliquot single-use volumes, and measure concentration rather than assuming complete recovery after filtration.