Seeds are often grouped with nuts, & why not? - "many nuts (in the culinary sense), such as almonds, pecans, pistachios, walnuts, and Brazil nuts, are not nuts in a botanical sense." [1a]
There are no PCa studies on seeds as a food group, or individually. Except for flaxseed, which I have dealt with in:
"Foods/Supplements-Vitamins: Flaxseed hull lignans - Enterolactone" &
"Foods/Supplements-Vitamins: Alpha-Linolenic Acid [ALA]"
& so I will try to dig up reasons why we should consider the others.
It seems to me that one has to work at getting a therapeutic dose of anything from seeds.
Secoisolariciresinol diglucoside [SDG].
"SDG is an antioxidant phytoestrogen present in flax, sunflower, sesame, and pumpkin seeds." [1b] "It is a precursor of mammal lignans" - enterodiol and enterolactone.
Flaxseed hulls (no fat) are the best source, but given the potential importance of the downstream lignans, it's worth noting that flax isn't the only source.
 Sesame seeds.
Sesame seeds are 50% fat, 5% water, 18% protein & 23% carbohydrate.
They are 19% oleic & 21% linoleic acid.
Phytosterols: 714mg / 100g.
"Sesamin, a lipid-soluble lignan, is one of the major constituents of sesame." [2a]
But there is also sesamol, and anthrasesamone F.
[2a] (2015 - China)
"Previous studies have reported that sesamin induces growth inhibition in human cancer cells, particularly prostate cancer cells. In the present study, we mainly explored the mechanism underlying the protective effect of sesamin on prostate cancer cell proliferation and invasion ..."
"... results suggest that the potential ability of sesamin to downregulate the secretion of cytokines and the expression of cell proliferative- and invasive-related gene products ... was shown to be via the p38 mitogen-activated protein kinase (p38-MAPK) and NF-κB signaling pathways ..."
[2b] (2010 - U.S. - The University of Texas M.D. Anderson Cancer Center, Houston)
"Sesamin manifests chemopreventive effects through the suppression of NF-kappa B-regulated cell survival, proliferation, invasion, and angiogenic gene products."
[2c] (2016 - China) "Phytochemical Contents and Antioxidant and Antiproliferative Activities of Selected Black and White Sesame Seeds"
From a health perspective, black sesame seeds are likely to be the most valuable.
"Fenheizhi3 (black) cultivar exhibited the maximum contents of total phenolics and lignans and values of total oxygen radical absorbance capacity (ORAC) and antiproliferative activity (EC50) against HepG2 cells."
[2d] Penzeys Spices is a good soure of black sesame seed (as well as the white).
 Coriander Seed.
[3a] (2014 - U.S. / Turkey)
"... purification of the roasted seed extracts afforded tripetroselinin as the predominant component."
"Other isolates were petroselinic acid, 1,3-dipetroselinin, 2-C-methyl-d-erythritol, 2-C-methyl-d-erythritol 4-O-β-d-glucopyranoside and linalool."
"... extracts of both raw and roasted seeds and pure isolates from them showed comparable antioxidant and anti-inflammatory activities to the positive controls used in the assays, and inhibited the growth of human tumour cells AGS (gastric carcinoma), DU-145 and LNCaP (prostate carcinoma), HCT-116 (colon carcinoma), MCF-7 (breast carcinoma) and NCI-H460 (lung carcinoma) by 4-34%, respectively."
 Fenugreek seed (Trigonella foenum-graecum) Used in Indian dishes. Contains:
- Diosgenin, a steroidal saponin
- flavonoids, alkaloids, coumarins, vitamins and saponins; the most prevalent alkaloid is trigonelline and coumarins include cinnamic acid and scopoletin [4a]
[4b] (2011 - U.S. / Taiwan)
"Diosgenin, a Steroidal Saponin, Inhibits Migration and Invasion of Human Prostate Cancer PC-3 Cells by Reducing Matrix Metalloproteinases Expression"
[4c] (2016 - China)
"Diosgenin‑induced autophagy and apoptosis in a human prostate cancer cell line."
 Charnushka - nigella sativa
Nigella has many misleading names: black caraway, black cumin & plenty more. It is also known as kalonji.
I came across it maybe 50 years ago, when I first had naan in an Indian restaurant in England. The kalonji seeds were sprinkled on the suface of the bread.
& then, about 40 years ago, our local supermarket had these gigantic loaves of Russian rye (at least 10 lbs), containing a liberal amount of charnushka. Quite addictive IMO.
Basically, I developed a taste for nigella that is very difficult to satisfy in Asheville, NC. The Smihsonian mag once had an article: "Nigella Seeds: What the Heck Do I Do with Those? [5b] I have a bag from Penzey's in my freezer [5c]
"Nigella sativa oil contains conjugated linoleic (18:2) acid, thymoquinone, nigellone (dithymoquinone), melanthin, nigilline, and trans-anethole." [5a]
[5d] (2014 - Turkey)
"Enhanced cytotoxicity and apoptosis by thymoquinone in combination with zoledronic acid in hormone- and drug-resistant prostate cancer cell lines."
[5e] (2014 - Turkey)
"Novel combination of docetaxel and thymoquinone induces synergistic cytotoxicity and apoptosis in DU-145 human prostate cancer cells by modulating PI3K-AKT pathway."
[5f] (2010 - U.S.)
"Studies on molecular mechanisms of growth inhibitory effects of thymoquinone against prostate cancer cells: role of reactive oxygen species."
[5g] (2008 - U.S.)
"Thymoquinone inhibits tumor angiogenesis and tumor growth through suppressing AKT and extracellular signal-regulated kinase signaling pathways."
[5h] (2007 - U.S.)
"Androgen receptor and E2F-1 targeted thymoquinone therapy for hormone-refractory prostate cancer."
 Pumpkin seeds (pepitas)
Pumpkin seeds are sometimes used against BPH. They are fairly high in zinc, so perhaps that's a reason. However, there is nothing to suggest benefit against PCa.
 No PCa results found for the following (although there are non-PCa papers for some of these):
- Anise Seed
- Caraway seed
- Celery seed
- Cumin seed
- Dill seed
- Fennel seed
- Mustard seed
- Poppy seed
- Sunflower seed