我們可能終於知道為什麼這麼多終生吸煙者從未患過肺癌

Recently Yahoo News on-line reported the following:

We may finally know why so many lifelong smokers never get lung cancer

BGR Joshua Hawkins

Tue, May 31, 2022, 12:26 PM

Scientists may have discovered why lifelong smokers never get lung cancer. That sentence probably seems silly, especially given that cigarettes are the number one risk factor for lung cancer. Despite tobacco products being the cause of 90 percent of deaths, lifelong smokers somehow tend to avoid getting lung cancer. Now, science may have finally figured out why that is.

According to new findings published in Nature Genetics, DNA repair genes could be keeping some smokers from getting lung cancer. Researchers found an inherent advantage in many smokers that never developed lung cancer. They found that the cells lining the lungs were less likely to mutate over time.

Essentially, because the DNA repair genes in some people who smoke were so active, they protected the person from forming cancer cells. It’s an intriguing find and one that could finally explain why some smokers never get lung cancer.

The researchers looked at the genetic profiles of 33 participants’ bronchial basal cells. All the participants were aged between 11 and 86 years old. 14 participants had never smoked, while the other 19 had varying histories of being light, moderate, and heavy smokers.

They then sequenced the gathered surface cells collected from the participants’ lungs to measure mutations in their genomes.

Multiplying Mutations

The results showed that these lung cells survive for years. And, that the mutations can accumulate as the person ages and continues to smoke. These are also the most likely of the lung’s cells to turn cancerous, a pulmonologist with Albert Einstein College of Medicine explained in a statement.

But what’s most interesting is that after around 23 years of smoking a pack a day, the scientists found that the risk and mutation rate of those cells plateaus drastically. As such, some lifelong smokers never get lung cancer because of how drastically the mutation rates change.

That’s because their DNA is able to repair the body before the cell mutations develop into tumors. These DNA repair genes can be inherited or acquired, scientists say. And exactly what makes one person’s body better at repairing DNA is still a mystery.

However, based on the findings of this study, it could play a large part in why 80 to 90 percent of lifelong smokers never develop lung cancer.

Still, even knowing this, the risk associated with smoking is still terribly high. And geneticists plan to develop new ways to measure a person’s capacity for DNA repair. This could help us better understand the part DNA repair plays in why lifelong smokers never get lung cancer. Additionally, it could even help us assess a person’s risk of getting lung cancer more effectively.

Translation

科學家們可能已經發現了為什麼終生吸煙者永遠不會患肺癌。這句話可能看起來很愚蠢，尤其是考慮到香煙是肺癌的第一大危險因素。儘管煙草製品是 90% 的死亡原因，但終生吸煙者往往可能會避免患上肺癌。現在，科學可能終於弄清楚了為什麼會這樣。

根據發表在《自然遺傳學》上的新發現，DNA 修復基因可能會阻止一些吸煙者患上肺癌。研究人員在許多從未患過肺癌的吸煙者身上發現了一種先天優勢。他們發現這些人肺內襯層的細胞隨著時間過去過去都不太可能發生突變。

從本質上講，因為一些吸煙者的 DNA 修復基因非常活躍，它們保護了這個人免於形成癌細胞。這是一個有趣的發現，最終可以解釋為什麼有些吸煙者永遠不會患上肺癌。

研究人員查看了 33 名參與者支氣管基底細胞的基因圖譜。所有參與者的年齡在 11 至 86 歲之間。 14 名參與者從未吸煙，而另外 19 名參與者是有輕度、中度和重度吸煙者的人。

然後，他們對從參與者肺部收集到的表面細胞去進行測序，以測量他們基因的突變。

倍增突變

結果表明，這些肺細胞可以存活多年。而且，突變會隨著人的年齡增長和繼續吸煙而積累。阿爾伯特愛因斯坦醫學院的肺病學家在一份聲明中解釋說，這些也是最有可能發生癌變的肺細胞。

但最有趣的是，在每天吸一包煙約 23 年後，科學家們發現這些細胞的突變和風險率急劇平稳。因此，一些終生吸煙的人從未患過肺癌，因為突變率發生了急劇的變化。

那是因為他們的 DNA 能夠在細胞突變發展成腫瘤之前修復身體。科學家說，這些 DNA 修復基因可以遺傳或從别處獲得。究竟是什麼讓一個人的身體更擅於修復 DNA 仍然是個謎。

然而，根據這項研究的結果，它可能在很大程度上解釋了為什麼 80% 到 90% 的終生吸煙者從未患上肺癌。

但即使知道這一點，與吸煙相關的風險仍然非常高。遺傳學家計劃開發新的方法來測量一個人的 DNA 修復能力。這可以幫助我們更好地理解 DNA 修復, 及在終生吸煙者為什麼永遠不會患肺癌中所起的作用。此外，它甚至可以幫助我們更有效地評估一個人患肺癌的風險。

So, in some people who actively smoke, because their DNA can repair the genes and thus protect the person from forming cancer cells. It’s an intriguing find and may explain why some chain smokers never get lung cancer.