Investigation 007
What the Slide Cannot Say
Three parasites cause cancer. Nobody is checking for a fourth.
Cancer, found and missed
H&E
Two dyes, pink and blue, unchanged since the 1870s. Almost every cancer diagnosis on earth is made on them.
What we are reading
Gathered for the investigation and not yet written up. Each note says what the paper does and does not show.
- Haghbin N, Oveisi B, Banitaba AP. Automated variable power cold microwave tissue processing: A novel universal tissue processing protocol without using formaldehyde and xylene.10.1016/j.acthis.2022.151880 · PMID 35344896
Used here for their MAS criteria — morphology, artifacts, staining — which is the honest list of what a pathologist is actually judging when they say a slide is adequate: cellular detail, tissue arrangement, tissue integrity, stain uptake, and visual distinction under LIGHT microscopy. Every one of those criteria is about human tissue architecture. None of them asks whether something non-human is present.
- Mewara A, Khurana S, Gupta S, Munda VS, Singh S, Sehgal R. Diagnostic performance of mini parasep solvent-free faecal parasite concentrator for the diagnosis of intestinal parasitic infections.10.4103/ijmm.IJMM_19_44 · PMID 32003337
The fact that breaks the simple version of the iodine story. In parasitology, IODINE MOUNT MICROSCOPY is a routine method for FINDING parasites — it is listed here alongside direct wet mount as standard practice, and the concentration methods improved the yield of Hymenolepis nana, Trichuris trichiura, Entamoeba coli and Giardia lamblia. Iodine kills protozoa and stains their nuclei so a human can identify them. In the laboratory that goes looking for parasites, iodine is the tool that reveals them. Whatever iodine does in a cancer specimen, 'makes the organism invisible' is not it.
Connected on the map
Also in Cancer, found and missed