Gum dis­ease bac­te­ria linked to esophageal cancer

Pakistan Observer - - KARACHI CITY -

IN A NEW study, re­searchers pro­pose for the first time that Por­phy­romonas gin­gi­valis - the bac­terium be­hind gum dis­ease - could be a risk fac­tor for esophageal cancer. The re­searchers, from the Univer­sity of Louisville (UofL), KY, and He­nan Univer­sity of Sci­ence and Tech­nol­ogy in Luoyang, China, re­port their find­ings in the jour­nal In­fec­tious Agents and Cancer. Ac­cord­ing to the Cen­ters for Dis­ease Con­trol and Preven­tion (CDC), every year, around 15,000 peo­ple in the US are di­ag­nosed with esophageal cancer - a cancer that starts in the esoph­a­gus or gul­let, the mus­cu­lar tube that moves food from the throat into the stom­ach.

The lin­ing of the esoph­a­gus is made of two kinds of cell, which is why there are two main types of esophageal cancer: esophageal ade­no­car­ci­noma and esophageal squa­mous cell car­ci­noma (ESCC). ESCC is more com­mon in de­vel­op­ing coun­tries. Known risk fac­tors for esophageal cancer in­clude chem­i­cal ex­po­sure, diet, hered­ity and age - all fac­tors al­ready com­mon to many other can­cers. The cancer is hard to di­ag­nose in the early stages. For many patients, the cancer de­vel­ops rapidly af­ter di­ag­no­sis and the prog­no­sis is not good.

For their study, the team tested tis­sue from 100 patients with ESCC and 30 patients who did not have the dis­ease (the con­trols). They tested sam­ples taken from three types of esophageal tis­sue: can­cer­ous tis­sue, non-can­cer­ous tis­sue ad­ja­cent to can­cer­ous tis­sue and nor­mal tis­sue from the con­trols. Co-se­nior au­thor Huizhi Wang, as­sis­tant pro­fes­sor of oral im­munol­ogy and in­fec­tious dis­eases at the UofL School of Den­tistry, says: “These find­ings pro­vide the first di­rect ev­i­dence that in­fec­tion could be a novel risk fac­tor for ESCC, and may also serve as a prog­nos­tic biomarker for this type of cancer.” He notes that if these find­ings are con­firmed, then it could mean that erad­i­ca­tion of a com­mon oral bac­terium could help re­duce the sig­nif­i­cant num­ber of peo­ple who de­velop ESCC.

To de­tect P. gin­gi­valis in the tis­sue sam­ples, the re­searchers mea­sured ex­pres­sion of lysineg­ingi­pain, an en­zyme unique to the bac­terium. They also looked for DNA traces of the bac­te­rial cell. They found lev­els of both the en­zyme and the bac­te­rial DNA were sig­nif­i­cantly higher in the can­cer­ous tis­sue of ESCC patients than in sur­round­ing tis­sue or tis­sue of nor­mal con­trols. The team found that lev­els of P. gin­gi­valis mea­sures were in line with lev­els of other mea­sures, such as ex­tent of cancer cell dif­fer­en­ti­a­tion, metas­ta­sis (ex­tent of spread) and over­all sur­vival rate.

Spec­u­lat­ing on pos­si­ble ex­pla­na­tions, Prof. Wang of­fers two. Ei­ther ESCC cells are a “pre­ferred niche” for the bac­terium to thrive in, or in­fec­tion with the bac­terium some­how spurs the de­vel­op­ment of the cancer. If the rea­son is that the cancer cells of­fer the bac­terium a niche, then sim­ple an­tibi­otics could be a way for­ward for treat­ment. An­other ap­proach could be to use genetic tech­nol­ogy to tar­get the bac­terium and ul­ti­mately elim­i­nate the cancer cells.

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