If glyphosate does in fact turn out to be dangerous, then some sort of carcinogenic secondary product seems like the most probable source of carcinogenicity for glyphosate. However, there seems to be a lot of confusion from glyphosate critics about which products to test and as a result, I'm not aware of any definitive research that shows a) there are secondary products which are relevant for glyphosate used as directed that b) also definitely cause cancer.
From your first link, Dr. Perry's belief that glyphosate might be clastogenic is certainly interesting, but also a little weird. The proposed mechanism is that glyphosate causes oxidative damage to to DNA which causes strand breakage. This is not a subtle mechanism and I would expect evidence for it to be readily available from simple tests like the Ames test. If you have the research he's using to support this claim, I'd definitely be interested in seeing it.
At the end of the day, we're left with the same haunting question however, if glyphosate so definitely causes cancer, then why has it been so hard to figure out? Monsanto is much smaller than the tobacco companies were so it's hard for me to believe that Monsanto masterminded some global conspiracy when they were only about the size of Expedia when Monsanto were bought out. Many of the most important papers critical of glyphosate have a number of issues. The IARC monograph seemed to deliberately exclude contradictory data, including a study that one of the monograph's writers was directly involved in. Even then, the monograph wasn't particularly definitive. The oft cited metastudy that came out in 2019 seemed like a big deal, but on closer inspection, they had decided that out of nearly 40 years of research, they would only examine 7 papers. Not to mention they also relied on data from exposure levels far in excess of directions provided by Monsanto.
The strongest conclusions we have about glyphosate seem to be that for exposure levels 10-100 times recommended by major health organizations and Monsanto there may be an increased chance of some cancers, though the effect doesn't seem to be large. This conclusion can get funky because some data (the IARC panel was criticized heavily for this) suggest that past a certain point, higher levels of glyphosate correlate with lower cancer rates.
From your first link, Dr. Perry's belief that glyphosate might be clastogenic is certainly interesting, but also a little weird. The proposed mechanism is that glyphosate causes oxidative damage to to DNA which causes strand breakage. This is not a subtle mechanism and I would expect evidence for it to be readily available from simple tests like the Ames test. If you have the research he's using to support this claim, I'd definitely be interested in seeing it.
At the end of the day, we're left with the same haunting question however, if glyphosate so definitely causes cancer, then why has it been so hard to figure out? Monsanto is much smaller than the tobacco companies were so it's hard for me to believe that Monsanto masterminded some global conspiracy when they were only about the size of Expedia when Monsanto were bought out. Many of the most important papers critical of glyphosate have a number of issues. The IARC monograph seemed to deliberately exclude contradictory data, including a study that one of the monograph's writers was directly involved in. Even then, the monograph wasn't particularly definitive. The oft cited metastudy that came out in 2019 seemed like a big deal, but on closer inspection, they had decided that out of nearly 40 years of research, they would only examine 7 papers. Not to mention they also relied on data from exposure levels far in excess of directions provided by Monsanto.
The strongest conclusions we have about glyphosate seem to be that for exposure levels 10-100 times recommended by major health organizations and Monsanto there may be an increased chance of some cancers, though the effect doesn't seem to be large. This conclusion can get funky because some data (the IARC panel was criticized heavily for this) suggest that past a certain point, higher levels of glyphosate correlate with lower cancer rates.